Polynucleotides encoding soluble zalpha11 cytokine receptors

ABSTRACT

Novel polypeptide combinations, polynucleotides encoding the polypeptides, and related compositions and methods are disclosed for soluble zalpha11 receptors that may be used as novel cytokine antagonists, and within methods for detecting ligands that stimulate the proliferation and/or development of hematopoietic, lymphoid and myeloid cells in vitro and in vivo. Ligand-binding receptor polypeptides can also be used to block zalpha11 Ligand activity in vitro and in vivo, and may be used in conjunction with zalpha11 Ligand and other cytokines to selectively stimulate the immune system. The present invention also includes methods for producing the protein, uses therefor and antibodies thereto.

REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/872,087, filed Jun. 18, 2004, now U.S. Pat. No. 7,189,695, whichclaims benefit of U.S. Provisional Application 60/194,731, filed on Apr.5, 2000, and U.S. Provisional Application 60/222,121, filed on Jul. 28,2000, all of which are incorporated by reference. Under 35 U.S.C. §119(e)(1), this application claims benefit of said ProvisionalApplications. Additionally, this application claims benefit ofapplication Ser. No. 09/825,561 filed on Apr. 3, 2001, issued as U.S.Pat. No. 6,777,539, under 35 U.S.C. 35 § 120.

BACKGROUND OF THE INVENTION

Hormones and polypeptide growth factors control proliferation anddifferentiation of cells of multicellular organisms. These diffusablemolecules allow cells to communicate with each other and act in concertto form cells and organs, and to repair damaged tissue. Examples ofhormones and growth factors include the steroid hormones (e.g. estrogen,testosterone), parathyroid hormone, follicle stimulating hormone, theinterleukins, platelet derived growth factor (PDGF), epidermal growthfactor (EGF), granulocyte-macrophage colony stimulating factor (GM-CSF),erythropoietin (EPO) and calcitonin.

Hormones and growth factors influence cellular metabolism by binding toreceptors. Receptors may be integral membrane proteins that are linkedto signaling pathways within the cell, such as second messenger systems.Other classes of receptors are soluble molecules, such as thetranscription factors. Of particular interest are receptors forcytokines, molecules that promote the proliferation and/ordifferentiation of cells. Examples of cytokines include erythropoietin(EPO), which stimulates the development of red blood cells;thrombopoietin (TPO), which stimulates development of cells of themegakaryocyte lineage; and granulocyte-colony stimulating factor(G-CSF), which stimulates development of neutrophils. These cytokinesare useful in restoring normal blood cell levels in patients sufferingfrom anemia, thrombocytopenia, and neutropenia or receiving chemotherapyfor cancer.

The demonstrated in vivo activities of these cytokines illustrate theenormous clinical potential of, and need for, other cytokines, cytokineagonists, and cytokine antagonists or binding partners. The presentinvention addresses these needs by providing a new cytokine antagonistor binding partner, a soluble hematopoietic cytokine receptor, as wellas related compositions and methods.

The present invention provides such polypeptides for these and otheruses that should be apparent to those skilled in the art from theteachings herein.

DESCRIPTION OF THE INVENTION

Within one aspect, the present invention provides an isolatedpolynucleotide that encodes a soluble receptor polypeptide comprising asequence of amino acid residues that is at least 90% identical to theamino acid sequence as shown in SEQ ID NO:6, and wherein the solublereceptor polypeptide encoded by the polynucleotide sequence binds aligand comprising a polypeptide of SEQ ID NO:10 or SEQ ID NO:47, orantagonizes the ligand activity. In one embodiment, the isolatedpolynucleotide is as disclosed above, wherein the soluble receptorpolypeptide encoded by the polynucleotide forms a homodimeric receptorcomplex.

Within another aspect, the present invention provides an isolatedpolynucleotide that encodes a soluble receptor polypeptide comprising asequence of amino acid residues that is at least 90% identical to theamino acid sequence as shown in SEQ ID NO:6, wherein the solublereceptor polypeptide encoded by the polynucleotide forms a heterodimericor multimeric receptor complex. In one embodiment, the isolatedpolynucleotide is as disclosed above, wherein the soluble receptorpolypeptide encoded by the polynucleotide forms a heterodimeric ormultimeric receptor complex further comprising a soluble Class Icytokine receptor.

In one embodiment, the isolated polynucleotide is as disclosed above,wherein the soluble receptor polypeptide encoded by the polynucleotideforms a heterodimeric or multimeric receptor complex further comprisinga soluble IL-2Rγ receptor polypeptide (SEQ ID NO:4) or a soluble IL-13α′receptor polypeptide (SEQ ID NO:82). In another embodiment, the isolatedpolynucleotide is as disclosed above, wherein the polypeptide furthercomprises a WSXWS motif as shown in SEQ ID NO:13.

Within another aspect, the present invention provides an isolatedpolynucleotide that encodes a soluble receptor polypeptide comprising asequence of amino acid residues as shown in SEQ ID NO:6, wherein thesoluble receptor polypeptide encoded by the polynucleotide forms aheterodimeric or multimeric receptor complex. In one embodiment, theisolated polynucleotide is as disclosed above, wherein the solublereceptor polypeptide encoded by the polynucleotide further comprises asoluble Class I cytokine receptor. In another embodiment, the isolatedpolynucleotide is as disclosed above, wherein the soluble receptorpolypeptide encoded by the polynucleotide forms a heterodimeric ormultimeric receptor complex further comprising a soluble IL-2Rγ receptorpolypeptide (SEQ ID NO:4) or a soluble IL-13α′ receptor polypeptide (SEQID NO:82). In another embodiment, the isolated polynucleotide is asdisclosed above, wherein the soluble receptor polypeptide is encoded bythe polynucleotide as shown in SEQ ID NO:7. In another embodiment, theisolated polynucleotide is as disclosed above, wherein the solublereceptor polypeptide further comprises an affinity tag.

Within a second aspect, the present invention provides an expressionvector comprising the following operably linked elements: (a) atranscription promoter; a first DNA segment encoding a soluble receptorpolypeptide having an amino acid sequence as shown in SEQ ID NO:6; and atranscription terminator; and (b) a second transcription promoter; asecond DNA segment encoding a soluble Class I cytokine receptorpolypeptide; and a transcription terminator; and wherein the first andsecond DNA segments are contained within a single expression vector orare contained within independent expression vectors. In one embodiment,the expression vector disclosed above further comprises a secretorysignal sequence operably linked to the first and second DNA segments. Inanother embodiment, the expression vector is as disclosed above, whereinthe second DNA segment encodes a soluble IL-2Rγ receptor polypeptide(SEQ ID NO:4) or a soluble IL-13α′ receptor polypeptide (SEQ ID NO:82).

Within a third aspect, the present invention provides a cultured cellcomprising an expression vector as disclosed above, wherein the cellexpresses the polypeptides encoded by the DNA segments. In oneembodiment, the cultured cell comprising an expression vector is asdisclosed above, wherein the first and second DNA segments are locatedon independent expression vectors and are co-transfected into the cell,and cell expresses the polypeptides encoded by the DNA segments. Inanother embodiment, the cultured cell comprising an expression vector isas disclosed above, wherein the cell expresses a heterodimeric ormultimeric soluble receptor polypeptide encoded by the DNA segments. Inanother embodiment, the cultured cell comprising an expression vector isas disclosed above, wherein the cell secretes a soluble receptorpolypeptide heterodimer or multimeric complex. In another embodiment,the cultured cell comprising an expression vector is as disclosed above,wherein the cell secretes a soluble receptor polypeptide heterodimer ormultimeric complex that binds a ligand comprising a polypeptide of SEQID NO:10 or SEQ ID NO:47, or antagonizes the ligand activity.

Within another aspect, the present invention provides a DNA constructencoding a fusion protein comprising: a first DNA segment encoding apolypeptide having a sequence of amino acid residues as shown in SEQ IDNO:6; and at least one other DNA segment encoding a soluble Class Icytokine receptor polypeptide, wherein the first and other DNA segmentsare connected in-frame; and wherein the first and other DNA segmentsencode the fusion protein. In one embodiment, the DNA construct encodesa fusion protein as disclosed above, wherein at least one other DNAsegment encodes a soluble IL-2Rγ receptor polypeptide (SEQ ID NO:4) or asoluble IL-13α′ receptor polypeptide (SEQ ID NO:82).

Within another aspect, the present invention provides an expressionvector comprising the following operably linked elements: atranscription promoter; a DNA construct encoding a fusion protein asdisclosed above; and a transcription terminator, wherein the promoter isoperably linked to the DNA construct, and the DNA construct is operablylinked to the transcription terminator.

Within another aspect, the present invention provides a cultured cellcomprising an expression vector as disclosed above, wherein the cellexpresses a polypeptide encoded by the DNA construct.

Within another aspect, the present invention provides a method ofproducing a fusion protein comprising: culturing a cell as disclosedabove; and isolating the polypeptide produced by the cell.

Within another aspect, the present invention provides an isolatedsoluble receptor polypeptide comprising a sequence of amino acidresidues that is at least 90% identical to an amino acid sequence asshown in SEQ ID NO:6, and wherein the soluble receptor polypeptide bindsa ligand comprising a polypeptide of SEQ ID NO:10 or SEQ ID NO:47, orantagonizes the ligand activity. In one embodiment, the isolatedpolypeptide is as disclosed above, wherein the soluble receptorpolypeptide forms a homodimeric receptor complex.

Within another aspect, the present invention provides an isolatedpolypeptide comprising a sequence of amino acid residues that is atleast 90% identical to an amino acid sequence as shown in SEQ ID NO:6,wherein the soluble receptor polypeptide forms a heterodimeric ormultimeric receptor complex. In one embodiment, the isolated polypeptideis as disclosed above, wherein the soluble receptor polypeptide forms aheterodimeric or multimeric receptor complex further comprising asoluble Class I cytokine receptor. In another embodiment, the isolatedpolypeptide is as disclosed above, wherein the soluble receptorpolypeptide forms a heterodimeric or multimeric receptor complex furthercomprising a soluble IL-2Rγ receptor polypeptide (SEQ ID NO:4) or asoluble IL-13α′ receptor polypeptide (SEQ ID NO:82). In anotherembodiment, the isolated polypeptide is as disclosed above, wherein thepolypeptide further comprises a WSXWS motif as shown in SEQ ID NO:13.

Within another aspect, the present invention provides an isolatedsoluble receptor polypeptide comprising a sequence of amino acidresidues as shown in SEQ ID NO:6, wherein the soluble receptorpolypeptide forms a heterodimeric or multimeric receptor complex. In oneembodiment, the isolated polypeptide is as disclosed above, wherein thesoluble receptor polypeptide forms a heterodimeric or multimericreceptor complex further comprising a soluble Class I cytokine receptor.In another embodiment, the isolated polypeptide is as disclosed above,wherein the soluble receptor polypeptide forms a heterodimeric ormultimeric receptor complex comprising a soluble IL-2Rγ receptorpolypeptide (SEQ ID NO:4) or a soluble IL-13α′ receptor polypeptide (SEQID NO:82). In another embodiment, the isolated polypeptide is asdisclosed above, wherein the soluble receptor polypeptide furthercomprises an affinity tag, chemical moiety, toxin, or label.

Within another aspect, the present invention provides an isolatedheterodimeric or multimetric soluble receptor complex comprising solublereceptor subunits, wherein at least one of soluble receptor subunitscomprises a soluble receptor polypeptide comprising a sequence of aminoacid residues as shown in SEQ ID NO:6. In one embodiment, the isolatedheterodimeric or multimetric soluble receptor complex disclosed abovefurther comprises a soluble Class I cytokine receptor polypeptide. Inanother embodiment, the isolated heterodimeric or multimetric solublereceptor complex disclosed above further comprises a soluble IL-2Rγreceptor polypeptide (SEQ ID NO:4) or a soluble IL-13α′ receptorpolypeptide (SEQ ID NO:82).

Within another aspect, the present invention provides a method ofproducing a soluble receptor polypeptide that form a heterodimeric ormultimeric complex comprising: culturing a cell as disclosed above; andisolating the soluble receptor polypeptides produced by the cell.

Within another aspect, the present invention provides a method ofproducing an antibody to a soluble receptor polypeptide comprising:inoculating an animal with a soluble receptor polypeptide complexselected from the group consisting of: (a) a polypeptide comprising ahomodimeric soluble receptor complex comprising SEQ ID NO:6; (b) apolypeptide comprising a soluble receptor heterodimeric or multimericreceptor complex comprising SEQ ID NO:6; (b) a polypeptide comprising asoluble receptor heterodimeric or multimeric receptor complex comprisingSEQ ID NO:6, and further comprising a soluble Class I cytokine receptorpolypeptide; (c) a polypeptide comprising a soluble receptorheterodimeric or multimeric receptor complex comprising SEQ ID NO:6, andfurther comprising a soluble IL-2Rγ receptor polypeptide (SEQ ID NO:4);(d) a polypeptide comprising a soluble receptor heterodimeric ormultimeric receptor complex comprising SEQ ID NO:6, and furthercomprising a soluble IL-13α′ receptor polypeptide (SEQ ID NO:82); andwherein the polypeptide complex elicits an immune response in the animalto produce the antibody; and isolating the antibody from the animal.

Within another aspect, the present invention provides an antibodyproduced by the method as disclosed above, which specifically binds to ahomodimeric, heterodimeric or multimeric receptor complex comprising asoluble receptor polypeptide comprising SEQ ID NO:6. In one embodimentthe antibody disclosed above is a monoclonal antibody.

Within another aspect, the present invention provides an antibody whichspecifically binds to a homodimeric, heterodimeric or multimericreceptor complex as disclosed above.

Within another aspect, the present invention provides a method forinhibiting a ligand comprising a polypeptide of SEQ ID NO:10 or SEQ IDNO:47, or antagonizing the ligand activity-induced proliferation ofhematopoietic cells and hematopoietic cell progenitors comprisingculturing bone marrow or peripheral blood cells with a compositioncomprising an amount of soluble receptor comprising SEQ ID NO:6sufficient to reduce proliferation of the hematopoietic cells in thebone marrow or peripheral blood cells as compared to bone marrow orperipheral blood cells cultured in the absence of soluble receptor. Inone embodiment the method is as disclosed above, wherein thehematopoietic cells and hematopoietic progenitor cells are lymphoidcells. In another embodiment the method is as disclosed above, whereinthe lymphoid cells are NK cells or cytotoxic T cells.

Within another aspect, the present invention provides a method ofreducing proliferation of neoplastic B or T cells comprisingadministering to a mammal with a B or T cell neoplasm an amount of acomposition of soluble receptor comprising SEQ ID NO:6 sufficient toreduce proliferation of the neoplastic B or T cells.

Within another aspect, the present invention provides a method ofsuppressing an immune response in a mammal exposed to an antigen orpathogen comprising: (1) determining a level of an antigen- orpathogen-specific antibody; (2) administering a composition of solublereceptor polypeptide comprising SEQ ID NO:6 in an acceptablepharmaceutical vehicle; (3) determining a post administration level ofantigen- or pathogen-specific antibody; (4) comparing the level ofantibody in step (1) to the level of antibody in step (3), wherein alack of increase or a decrease in antibody level is indicative ofsuppressing an immune response.

These and other aspects of the invention will become evident uponreference to the following detailed description of the invention.

Prior to setting forth the invention in detail, it may be helpful to theunderstanding thereof to define the following terms:

The term “affinity tag” is used herein to denote a polypeptide segmentthat can be attached to a second polypeptide to provide for purificationor detection of the second polypeptide or provide sites for attachmentof the second polypeptide to a substrate. In principal, any peptide orprotein for which an antibody or other specific binding agent isavailable can be used as an affinity tag. Affinity tags include apoly-histidine tract, protein A (Nilsson et al., EMBO J. 4:1075, 1985;Nilsson et al., Methods Enzymol. 198:3, 1991), glutathione S transferase(Smith and Johnson, Gene 67:31, 1988), Glu-Glu affinity tag(Grussenmeyer et al., Proc. Natl. Acad. Sci. USA 82:7952-4, 1985),substance P, Flag™ peptide (Hopp et al., Biotechnology 6:1204-10, 1988),streptavidin binding peptide, or other antigenic epitope or bindingdomain. See, in general, Ford et al., Protein Expression andPurification 2: 95-107, 1991. DNAs encoding affinity tags are availablefrom commercial suppliers (e.g., Pharmacia Biotech, Piscataway, N.J.).

The terms “amino-terminal” and “carboxyl-terminal” are used herein todenote positions within polypeptides. Where the context allows, theseterms are used with reference to a particular sequence or portion of apolypeptide to denote proximity or relative position. For example, acertain sequence positioned carboxyl-terminal to a reference sequencewithin a polypeptide is located proximal to the carboxyl terminus of thereference sequence, but is not necessarily at the carboxyl terminus ofthe complete polypeptide.

The term “complement/anti-complement pair” denotes non-identicalmoieties that form a non-covalently associated, stable pair underappropriate conditions. For instance, biotin and avidin (orstreptavidin) are prototypical members of a complement/anti-complementpair. Other exemplary complement/anti-complement pairs includereceptor/ligand pairs, antibody/antigen (or hapten or epitope) pairs,sense/antisense polynucleotide pairs, and the like. Where subsequentdissociation of the complement/anti-complement pair is desirable, thecomplement/anti-complement pair preferably has a binding affinity of<10⁹ M⁻¹.

The term “complements of a polynucleotide molecule” is a polynucleotidemolecule having a complementary base sequence and reverse orientation ascompared to a reference sequence. For example, the sequence 5′ ATGCACGGG3′ is complementary to 5′ CCCGTGCAT 3′.

The term “degenerate nucleotide sequence” denotes a sequence ofnucleotides that includes one or more degenerate codons (as compared toa reference polynucleotide molecule that encodes a polypeptide).Degenerate codons contain different triplets of nucleotides, but encodethe same amino acid residue (i.e., GAU and GAC triplets each encodeAsp).

The term “expression vector” is used to denote a DNA molecule, linear orcircular, that comprises a segment encoding a polypeptide of interestoperably linked to additional segments that provide for itstranscription. Such additional segments include promoter and terminatorsequences, and may also include one or more origins of replication, oneor more selectable markers, an enhancer, a polyadenylation signal, etc.Expression vectors are generally derived from plasmid or viral DNA, ormay contain elements of both.

The term “isolated”, when applied to a polynucleotide, denotes that thepolynucleotide has been removed from its natural genetic milieu and isthus free of other extraneous or unwanted coding sequences, and is in aform suitable for use within genetically engineered protein productionsystems. Such isolated molecules are those that are separated from theirnatural environment and include cDNA and genomic clones. Isolated DNAmolecules of the present invention are free of other genes with whichthey are ordinarily associated, but may include naturally occurring 5′and 3′ untranslated regions such as promoters and terminators. Theidentification of associated regions will be evident to one of ordinaryskill in the art (see for example, Dynan and Tijan, Nature 316:774-78,1985).

An “isolated” polypeptide or protein is a polypeptide or protein that isfound in a condition other than its native environment, such as apartfrom blood and animal tissue. In a preferred form, the isolatedpolypeptide is substantially free of other polypeptides, particularlyother polypeptides of animal origin. It is preferred to provide thepolypeptides in a highly purified form, i.e. greater than 95% pure, morepreferably greater than 99% pure. When used in this context, the term“isolated” does not exclude the presence of the same polypeptide inalternative physical forms, such as dimers or alternatively glycosylatedor derivatized forms.

The term “operably linked”, when referring to DNA segments, indicatesthat the segments are arranged so that they function in concert fortheir intended purposes, e.g., transcription initiates in the promoterand proceeds through the coding segment to the terminator.

The term “ortholog” denotes a polypeptide or protein obtained from onespecies that is the functional counterpart of a polypeptide or proteinfrom a different species. Sequence differences among orthologs are theresult of speciation.

“Paralogs” are distinct but structurally related proteins made by anorganism. Paralogs are believed to arise through gene duplication. Forexample, α-globin, β-globin, and myoglobin are paralogs of each other.

A “polynucleotide” is a single- or double-stranded polymer ofdeoxyribonucleotide or ribonucleotide bases read from the 5′ to the 3′end. Polynucleotides include RNA and DNA, and may be isolated fromnatural sources, synthesized in vitro, or prepared from a combination ofnatural and synthetic molecules. Sizes of polynucleotides are expressedas base pairs (abbreviated “bp”), nucleotides (“nt”), or kilobases(“kb”). Where the context allows, the latter two terms may describepolynucleotides that are single-stranded or double-stranded. When theterm is applied to double-stranded molecules it is used to denoteoverall length and will be understood to be equivalent to the term “basepairs”. It will be recognized by those skilled in the art that the twostrands of a double-stranded polynucleotide may differ slightly inlength and that the ends thereof may be staggered as a result ofenzymatic cleavage; thus all nucleotides within a double-strandedpolynucleotide molecule may not be paired.

A “polypeptide” is a polymer of amino acid residues joined by peptidebonds, whether produced naturally or synthetically. Polypeptides of lessthan about 10 amino acid residues are commonly referred to as“peptides”.

“Probes and/or primers” as used herein can be RNA or DNA. DNA can beeither cDNA or genomic DNA. Polynucleotide probes and primers are singleor double-stranded DNA or RNA, generally synthetic oligonucleotides, butmay be generated from cloned cDNA or genomic sequences or itscomplements. Analytical probes will generally be at least 20 nucleotidesin length, although somewhat shorter probes (14-17 nucleotides) can beused. PCR primers are at least 5 nucleotides in length, preferably 15 ormore nt, more preferably 20-30 nt. Short polynucleotides can be usedwhen a small region of the gene is targeted for analysis. For grossanalysis of genes, a polynucleotide probe may comprise an entire exon ormore. Probes can be labeled to provide a detectable signal, such as withan enzyme, biotin, a radionuclide, fluorophore, chemiluminescer,paramagnetic particle and the like, which are commercially availablefrom many sources, such as Molecular Probes, Inc., Eugene, Oreg., andAmersham Corp., Arlington Heights, Ill., using techniques that are wellknown in the art.

The term “promoter” is used herein for its art-recognized meaning todenote a portion of a gene containing DNA sequences that provide for thebinding of RNA polymerase and initiation of transcription. Promotersequences are commonly, but not always, found in the 5′ non-codingregions of genes.

A “protein” is a macromolecule comprising one or more polypeptidechains. A protein may also comprise non-peptidic components, such ascarbohydrate groups. Carbohydrates and other non-peptidic substituentsmay be added to a protein by the cell in which the protein is produced,and will vary with the type of cell. Proteins are defined herein interms of their amino acid backbone structures; substituents such ascarbohydrate groups are generally not specified, but may be presentnonetheless.

The term “receptor” is used herein to denote a cell-associated protein,or a polypeptide subunit of such a protein, that binds to a bioactivemolecule (the “ligand”) and mediates the effect of the ligand on thecell. Binding of ligand to receptor results in a conformational changein the receptor (and, in some cases, receptor multimerization, i.e.,association of identical or different receptor subunits) that causesinteractions between the effector domain(s) and other molecule(s) in thecell. These interactions in turn lead to alterations in the metabolismof the cell. Metabolic events that are linked to receptor-ligandinteractions include gene transcription, phosphorylation,dephosphorylation, cell proliferation, increases in cyclic AMPproduction, mobilization of cellular calcium, mobilization of membranelipids, cell adhesion, hydrolysis of inositol lipids and hydrolysis ofphospholipids. Cell-surface cytokine receptors are characterized by amulti-domain structure as discussed in more detail below. Thesereceptors are anchored in the cell membrane by a transmembrane domaincharacterized by a sequence of hydrophobic amino acid residues(typically about 21-25 residues), which is commonly flanked bypositively charged residues (Lys or Arg). In general, receptors can bemembrane bound, cytosolic or nuclear; monomeric (e.g., thyroidstimulating hormone receptor, beta-adrenergic receptor) or multimeric(e.g., PDGF receptor, growth hormone receptor, IL-3 receptor, GM-CSFreceptor, G-CSF receptor, erythropoietin receptor and IL-6 receptor).The term “receptor polypeptide” is used to denote complete receptorpolypeptide chains and portions thereof, including isolated functionaldomains (e.g., ligand-binding domains).

A “secretory signal sequence” is a DNA sequence that encodes apolypeptide (a “secretory peptide”) that, as a component of a largerpolypeptide, directs the larger polypeptide through a secretory pathwayof a cell in which it is synthesized. The larger peptide is commonlycleaved to remove the secretory peptide during transit through thesecretory pathway.

A “soluble receptor” is a receptor polypeptide that is not bound to acell membrane. Soluble receptors are most commonly ligand-bindingreceptor polypeptides that lack transmembrane and cytoplasmic domains.Soluble receptors can comprise additional amino acid residues, such asaffinity tags that provide for purification of the polypeptide orprovide sites for attachment of the polypeptide to a substrate, orimmunoglobulin constant region sequences. Many cell-surface receptorshave naturally occurring, soluble counterparts that are produced byproteolysis. Soluble receptor polypeptides are said to be substantiallyfree of transmembrane and intracellular polypeptide segments when theylack sufficient portions of these segments to provide membrane anchoringor signal transduction, respectively.

The term “splice variant” is used herein to denote alternative forms ofRNA transcribed from a gene. Splice variation arises naturally throughuse of alternative splicing sites within a transcribed RNA molecule, orless commonly between separately transcribed RNA molecules, and mayresult in several mRNAs transcribed from the same gene. Splice variantsmay encode polypeptides having altered amino acid sequence. The termsplice variant is also used herein to denote a protein encoded by asplice variant of an mRNA transcribed from a gene.

Molecular weights and lengths of polymers determined by impreciseanalytical methods (e.g., gel electrophoresis) will be understood to beapproximate values. When such a value is expressed as “about” X or“approximately” X, the stated value of X will be understood to beaccurate to ±10%.

All references cited herein are incorporated by reference in theirentirety.

The present invention is based in part upon the discovery of a novelheterodimeric soluble receptor protein having the structure of a class Icytokine receptor. The heterodimeric soluble receptor includes at leastone zalpha11 soluble receptor subunit, disclosed in the commonly ownedU.S. patent application Ser. No. 09/404,641. A second soluble receptorpolypeptide included in the heterodimeric soluble receptor belongs tothe receptor subfamily that includes the IL-2 γ-common receptor (IL-2Rγ,or γ_(C)), IL-2 receptor β-subunit, and the β-common receptor (i.e.,IL3, IL-5, IL-13, IL-15 and GM-CSF receptor β-subunits), IL-13α,IL-13α′, IL-15 receptor subunits, and the like. The soluble human andmouse zalpha11 receptor (IL-21R) monomer and homodimer was shown toantagonize of the activity of the natural ligand for the zalpha11receptor, zalpha11 Ligand (IL-21) (Parrish-Novak, J. et al., Nature408:57-63, 2000). The zalpha11 Ligand is disclosed in the commonly ownedU.S. patent application Ser. No. 09/522,217. According to the presentinvention, a heterodimeric soluble zalpha11 receptor, as exemplified bya preferred embodiment of a soluble zalpha11 receptor+soluble IL-2Rγreceptor heterodimer (zalpha11/IL-2Rγ), was shown to act as a potentantagonist of the zalpha11 Ligand. As disclosed in the examples herein,the preferred zalpha11/IL-2Rγ heterodimer was a more effectiveantagonist zalpha11 Ligand activity, and hence more superior antagonist,than a zalpha11 homodimer or monomer.

Moreover, also contemplated by the present invention are homodimeric andmonomeric zalpha11-comprising soluble receptors; as well as homodimeric,heterodimeric, and multimeric zalpha11-comprising receptors that arecapable of intracellular signaling. Such receptors can comprise at leastone an extracellular domain of a zalpha11 receptor, and an intracellulardomain from zalpha11 or another class I cytokine receptor. Theadditional heterodimeric or multimeric subunit can comprise theextracellular domain from IL-2Rγ receptor (e.g., SEQ ID NO:4), IL-13α(also known as IL-13RA2; SEQ ID NO:84), IL-13α′ (also known as IL-13RA1;SEQ ID NO:82, IL-15 (SEQ ID NO:86) receptor, or other class I receptor,and an intracellular domain from zalpha11 or another class I cytokinereceptor.

The nucleotide sequence of a representative zalpha11-encoding DNA isdescribed in SEQ ID NO:1 (from nucleotide 1 to 1614), and its deduced538 amino acid sequence is described in SEQ ID NO:2. In its entirety,the zalpha11 polypeptide (SEQ ID NO:2) represents a full-lengthpolypeptide segment (residue 1 (Met) to residue 538 (Ser) of SEQ IDNO:2). The domains and structural features of the zalpha11 polypeptideare further described below.

Analysis of the zalpha11 polypeptide encoded by the DNA sequence of SEQID NO:1 revealed an open reading frame encoding 538 amino acids (SEQ IDNO:2) comprising a predicted secretory signal peptide of 19 amino acidresidues (residue 1 (Met) to residue 19 (Gly) of SEQ ID NO:2), and amature polypeptide of 519 amino acids (residue 20 (Cys) to residue 538(Ser) of SEQ ID NO:2). In addition to the WSXWS motif (SEQ ID NO:13)corresponding to residues 214 to 218 of SEQ ID NO:2, the receptorcomprises a cytokine-binding domain of approximately 200 amino acidresidues (residues 20 (Cys) to 237 (His) of SEQ ID NO:2); a domainlinker (residues 120 (Pro) to 123 (Pro) of SEQ ID NO:2); a penultimatestrand region (residues 192 (Lys) to 202 (Ala) of SEQ ID NO:2); atransmembrane domain (residues 238 (Leu) to 255 (Leu) of SEQ ID NO:2);complete intracellular signaling domain (residues 256 (Lys) to 538 (Ser)of SEQ ID NO:2) which contains a “Box I” signaling site (residues 267(Ile) to 273 (Pro) of SEQ ID NO:2), and a “Box II” signaling site(residues 301 (Leu) to 304 (Gly) of SEQ ID NO:2). Moreover, there is aSTAT3 binding site (YXXQ) located near the C-terminus from residues 519(Tyr) to 522 (Gln) of SEQ ID NO:2. Those skilled in the art willrecognize that these domain boundaries are approximate, and are based onalignments with known proteins and predictions of protein folding. Inaddition to these domains, conserved receptor features in the encodedreceptor include (as shown in SEQ ID NO:2) a conserved Trp residue atposition 138, and a conserved Arg residue at position 201. Moreover thezalpha11 contains conserved Cys residues typical of class I cytokinereceptors, shown in residues 25, 35, 65, and 81 of SEQ ID NO:2, andcorresponding regions of SEQ ID NO:6 and SEQ ID NO:69 described below.The corresponding polynucleotides encoding the zalpha11 polypeptideregions, domains, motifs, residues and sequences described above are asshown in SEQ ID NO:1. The human zalpha11 soluble receptor polypeptide,comprising residues 20 (Cys) to 237 (His) of SEQ ID NO:2, is shown inSEQ ID NO:6, and the corresponding polynucleotide sequence for the humanzalpha11 soluble receptor polypeptide is shown in SEQ ID NO:5.

SEQ ID NO:3 is a polynucleotide sequence comprising a fragment of thehuman IL-2Rγ receptor that encodes a soluble 232 amino acid solubleIL-2Rγ receptor polypeptide (SEQ ID NO:4). Those skilled in the art willrecognize that these domain boundaries for the IL-2Rγ receptorextracellular domain are approximate, and other soluble IL-2Rγ receptorpolypeptides, such as those including an IL-2Rγ receptor polypeptidesecretory signal sequence or additional IL-2Rγ receptor polypeptideamino acids in the extracellular domain, are encompassed within thescope of the present invention.

A variant form of the human zalpha11 polypeptide was identified (WIPOpublication No. WO 00/27822 shown as SEQ ID NO:3 and SEQ ID NO:4therein) and is shown in the DNA sequence of SEQ ID NO:64; andcorresponding polypeptide sequence shown in (SEQ ID NO:65). Thisparticular alternative zalpha11 receptor polypeptide contains 568 aminoacids, and comprises a predicted secretory signal peptide of 20 aminoacid residues (residue 1 (Met) to residue 20 (Gly) of SEQ ID NO:65), anda mature polypeptide of 548 amino acids (residue 21 (Met) to residue 568(Ser) of SEQ ID NO:65). In addition to the WSXWS motif (SEQ ID NO:13)corresponding to residues 244 to 248 of SEQ ID NO:65, the receptorcomprises a cytokine-binding domain of approximately 200 amino acidresidues (residues 21 (Met) to 267 (His) of SEQ ID NO:65); no domainlinker; a penultimate strand region (residues 222 (Lys) to 232 (Ala) ofSEQ ID NO:65); a transmembrane domain (residues 268 (Leu) to 285 (Leu)of SEQ ID NO:65); complete intracellular signaling domain (residues 286(Lys) to 568 (Ser) of SEQ ID NO:65) which contains a “Box I” signalingsite (residues 297 (Ile) to 303 (Pro) of SEQ ID NO:65), and a “Box II”signaling site (residues 331 (Leu) to 334 (Gly) of SEQ ID NO:65).Moreover, there is a STAT3 binding site (YXXQ) located near theC-terminus from residues 549 (Tyr) to 552 (Gln) of SEQ ID NO:65. Thoseskilled in the art will recognize that these domain boundaries areapproximate, and are based on alignments with known proteins andpredictions of protein folding. In addition to these domains, conservedreceptor features in the encoded receptor include (as shown in SEQ IDNO:65) a conserved Trp residue at position 168, and a conserved Argresidue at position 231. The corresponding polynucleotides encoding thezalpha11 polypeptide regions, domains, motifs, residues and sequencesdescribed above are as shown in SEQ ID NO:64. This particular humanzalpha11 soluble receptor variant polypeptide, comprising residues 21(Met) to 267 (His) of SEQ ID NO:65 (SEQ ID NO:69) and the correspondingpolynucleotide sequence for this particular human zalpha11 solublereceptor polypeptide is shown in SEQ ID NO:68. This variant form of thehuman zalpha11 receptor is included in the heterodimeric and multimericzalpha11 receptor complexes of the present invention, disclosed herein.

In addition, other variant forms of zalpha11 receptor are contemplatedby the present invention, wherein the extracellular domain of thevariant form disclosed above (e.g., 21 (Met) to 267 (His) of SEQ IDNO:65, or SEQ ID NO:69) comprises a domain linker comprising the aminoacids PAPP (SEQ ID NO:70) inserted between amino acid 161 (Ser) and 162(Arg) of SEQ ID NO:65, or the corresponding region of SEQ ID NO:69. Apreferred domain linker comprises a sequence of amino acids frompreferably 4 to 14 amino acids long, most preferably 14 amino acidslong, wherein aside from the PAPP (SEQ ID NO:70) motif sequence anyamino acid may be present. For example, a representativelinker-containing variant zalpha11 soluble receptor is shown in SEQ IDNO:71. Moreover, other variant zalpha11 sequences can include, inreference to SEQ ID NO:65 a Gly at position 162 rather than an Arg, orthe same Arg to Gly substitution in the corresponding region of SEQ IDNO:69 or SEQ ID NO:71, or other variant of SEQ ID NO:65 or SEQ ID NO:69containing a domain linker as described above. Corresponding DNAsequences that encode such variants can be readily determined by one ofskill in the art upon using the information present in Table 1 and Table2.

The zalpha11 Ligand is a “short-helix” form secreted four-helical bundlecytokine. The zalpha11 Ligand polynucleotide sequence is shown in SEQ IDNO:9 and corresponding amino acid sequence shown in SEQ ID NO:10. Thesecretory signal sequence comprises amino acid residues 1 (Met) to 31(Gly), and the mature polypeptide comprises amino acid residues 32 (Gln)to 162 (Ser) (as shown in SEQ ID NO:10). In general, cytokines arepredicted to have a four-alpha helix structure, with helices A, C and Dbeing most important in ligand-receptor interactions, and are morehighly conserved among members of the family. Referring to the humanzalpha11 Ligand amino acid sequence shown in SEQ ID NO:10, alignment ofhuman zalpha11 Ligand, human IL-15, human IL-4, and human GM-CSF aminoacid sequences it is predicted that zalpha11 Ligand helix A is definedby amino acid residues 41-56; helix B by amino acid residues 69-84;helix C by amino acid residues 92-105; and helix D by amino acidresidues 135-148; as shown in SEQ ID NO:10. Structural analysis suggeststhat the A/B loop is long, the B/C loop is short and the C/D loop isparallel long. Conserved cysteine residues within zalpha11 Ligandcorrespond to amino acid residues 71, 78, 122 and 125 of SEQ ID NO:10.Consistent cysteine placement is further confirmation of thefour-helical-bundle structure. Also highly conserved in the familycomprising IL-15, IL-2, IL-4, GM-CSF and zalpha11 Ligand is theGlu-Phe-Leu sequence as shown in SEQ ID NO:10 at residues 136-138.

Further analysis of zalpha11 Ligand based on multiple alignments ofknown cytokines predicts that amino acid residues 44, 47 and 135 (asshown in SEQ ID NO:10) play an important role in zalpha11 Ligand bindingto its cognate receptor. Based on comparison between sequences of humanand murine zalpha11 Ligand well-conserved residues were found in theregions predicted to encode alpha helices A and D. The correspondingpolynucleotides encoding the zalpha11 Ligand polypeptide regions,domains, motifs, residues and sequences described herein are as shown inSEQ ID NO:9. The murine zalpha11 Ligand is shown in SEQ ID NO:46, andcorresponding polypeptide sequence shown in SEQ ID NO:47.

The activity of molecules of the present invention can be measured usinga variety of assays that measure proliferation of and/or binding tocells expressing the zalpha11 receptor. Of particular interest arechanges in zalpha11 Ligand-dependent cells. A suitable cell line wasengineered to be zalpha11 Ligand-dependent that comprises anIL-3-dependent BaF3 cell line (Palacios and Steinmetz, Cell 41: 727-734,1985; Mathey-Prevot et al., Mol. Cell. Biol. 6: 4133-4135, 1986).Moreover, other suitable cell lines to be engineered to be zalpha11Ligand-dependent include FDC-P1 (Hapel et al., Blood 64: 786-790, 1984);and MO7e (Kiss et al., Leukemia 7: 235-240, 1993). Growthfactor-dependent cell lines can be established according to publishedmethods (e.g. Greenberger et al., Leukemia Res. 8: 363-375, 1984; Dexteret al., in Baum et al. Eds., Experimental Hematology Today, 8th Ann.Mtg. Int. Soc. Exp. Hematol. 1979, 145-156, 1980).

Zalpha11 Ligand stimulates proliferation, activation, differentiationand/or induction or inhibition of specialized cell function of cellsinvolved homeostasis of hematopoiesis and immune function. Inparticular, zalpha11 Ligand polypeptides stimulate proliferation,activation, differentiation, induction or inhibition of specialized cellfunctions of cells of the hematopoietic lineages, including, but notlimited to, T cells, B cells, NK cells, dendritic cells, monocytes, andmacrophages, as well as epithelial cells. Proliferation and/ordifferentiation of hematopoietic cells can be measured in vitro usingcultured cells or in vivo by administering zalpha11 Ligand to theappropriate animal model. Assays measuring cell proliferation ordifferentiation are well known in the art and described herein. Forexample, assays measuring proliferation include such assays aschemosensitivity to neutral red dye (Cavanaugh et al., InvestigationalNew Drugs 8:347-354, 1990, incorporated herein by reference),incorporation of radiolabeled nucleotides (Cook et al., AnalyticalBiochem. 179:1-7, 1989, incorporated herein by reference), incorporationof 5-bromo-2′-deoxyuridine (BrdU) in the DNA of proliferating cells(Porstmann et al., J. Immunol. Methods 82:169-179, 1985, incorporatedherein by reference), and use of tetrazolium salts (Mosmann, J. Immunol.Methods 65:55-63, 1983; Alley et al., Cancer Res. 48:589-601, 1988;Marshall et al., Growth Reg. 5:69-84, 1995; and Scudiero et al., CancerRes. 48:4827-4833, 1988; all incorporated herein by reference). Assaysmeasuring differentiation include, for example, measuring cell-surfacemarkers associated with stage-specific expression of a tissue, enzymaticactivity, functional activity or morphological changes (Watt, FASEB,5:281-284, 1991; Francis, Differentiation 57:63-75, 1994; Raes, Adv.Anim. Cell Biol. Technol. Bioprocesses, 161-171, 1989; all incorporatedherein by reference). Conversely, these assays can be used in acompetition to assess the antagonist or zalpha11 Ligand binding activityof the soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ receptors of the presentinvention. Moreover, the soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ receptors ofthe present invention can be used as an antagonist or Ligand bindingagent to modulate the immune system and hematopoietic activities of thezalpha11 Ligand.

Zalpha11 Ligand was isolated from tissue known to have importantimmunological function and which contain cells that play a role in theimmune system. Zalpha11 Ligand is expressed in CD3+ selected, activatedperipheral blood cells, and it has been shown that zalpha11 Ligandexpression increases after T cell activation. Moreover, results ofexperiments described in commonly owned U.S. patent application Ser. No.09/522,217, and the Examples section herein, demonstrate that zalpha11Ligand has an effect on the growth/expansion and/or differentiated stateof NK cells or NK progenitors. Additional evidence demonstrates thatzalpha11 Ligand affects proliferation and/or differentiation of T cellsand B cells in vivo. Factors that both stimulate proliferation ofhematopoietic progenitors and activate mature cells are generally known.NK cells are responsive to IL-2 alone, but proliferation and activationgenerally require additional growth factors. For example, it has beenshown that IL-7 and Steel Factor (c-kit ligand) were required for colonyformation of NK progenitors. IL-15+IL-2 in combination with IL-7 andSteel Factor was more effective (Mrózek et al., Blood 87:2632-2640,1996). However, unidentified cytokines may be necessary forproliferation of specific subsets of NK cells and/or NK progenitors(Robertson et. al., Blood 76:2451-2438, 1990). A composition comprisingzalpha11 Ligand and IL-15 stimulates NK progenitors and NK cells, withevidence that this composition is more potent than previously describedfactors and combinations of factors. Such compositions can furthercomprise kit ligand or stem cell factor. Thus, the soluble zalpha11receptor or soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ receptors of the present invention can be used as anantagonist or Ligand binding agent to decrease the activity of thezalpha11 Ligand on NK cells.

Moreover, the tissue distribution of a receptor for a given cytokineoffers a strong indication of the potential sites of action of thatcytokine. Northern analysis of zalpha11 receptor revealed transcripts inhuman spleen, thymus, lymph node, bone marrow, and peripheral bloodleukocytes. Specific cell types were identified as expressing zalpha11receptors, and strong signals were seen in a mixed lymphocyte reaction(MLR) and in the Burkitt's lymphoma Raji. The two monocytic cell lines,THP-1 (Tsuchiya et al., Int. J. Cancer 26:171-176, 1980) and U937(Sundstrom et al., Int. J. Cancer 17:565-577, 1976), were negative.Zalpha11 receptor is expressed at relatively high levels in the MLR, inwhich peripheral blood mononuclear cells (PBMNC) from two individualsare mixed, resulting in mutual activation. Detection of high levels oftranscript in the MLR but not in resting T or B cell populationssuggests that zalpha11 receptor expression may be induced in one or morecell types during activation. Activation of isolated populations of Tand B cells can be artificially achieved by stimulating cells with PMAand Ionomycin. When sorted cells were subjected to these activationconditions, levels of zalpha11 receptor transcript increased in bothcell types, supporting a role for this receptor and zalpha11 Ligand inimmune responses, especially in autocrine and paracrine T and B cellexpansions during activation. Zalpha11 Ligand may also play a role inthe expansion of more primitive progenitors involved in lymphopoiesis.Thus, the soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ receptors of the presentinvention can be used as an antagonist or Ligand binding agent tomodulate the lymphopoietic activities of the zalpha11 Ligand.

Zalpha11 receptor was found to be present at low levels in resting T andB cells, and was upregulated during activation in both cell types.Interestingly, the B cells also down-regulate the message more quicklythan do T cells, suggesting that amplitude of signal and timing ofquenching of signal are important for the appropriate regulation of Bcell responses.

In addition, a large proportion of intestinal lamina propria cells showpositive hybridization signals with zalpha11 receptor. This tissueconsists of a mixed population of lymphoid cells, including activatedCD4+ T cells and activated B cells. Immune dysfunction, in particularchronic activation of the mucosal immune response, plays an importantrole in the etiology of Crohn's disease and inflammatory bowel disease(IBD); abnormal response to and/or production of proinflammatorycytokines is also a suspected factor (Braegger et al., Annals Allergy72:135-141, 1994; Sartor R B Am. J. Gastroenterol. 92:5S-11S, 1997). Thezalpha11 Ligand in concert with IL-15 expands NK cells from bone marrowprogenitors and augments NK cell effector function. Zalpha11 Ligand alsoco-stimulates mature B cells stimulated with anti-CD40 antibodies, butinhibits B cell proliferation to signals through IgM. Zalpha11 Ligandenhances T cell proliferation in concert with a signal through the Tcell receptor, and over expression in transgenic mice leads tolymphopenia and an expansion of monocytes and granulocytes. Thesepleiotropic effects of zalpha11 Ligand suggest that molecules thatantagonize or bind zalpha11 Ligand, such as the molecules of the presentinvention, can provide therapeutic utility for a wide range of diseasesarising from defects in the immune system, including (but not limitedto) systemic lupus erythematosus (SLE), rheumatoid arthritis (RA),multiple sclerosis (MS), myasthenia gravis, Crohn's Disease, IBD, anddiabetes. It is important to note that these diseases are the result ofa complex network of immune dysfunction (SLE, for example, is themanifestation of defects in both T and B cells), and that immune cellsare dependent upon interaction with one another to elicit a potentimmune response. Therefore, zalpha11 Ligand (or an antagonist of theLigand, such a molecule of the present invention) that can be used tomanipulate more than one type of immune cell is an attractivetherapeutic candidate for intervention at multiple stages of disease.

Similarly, the tissue distribution of the mRNA corresponding to IL-2Rγreceptor cDNA shows expression in hematopoietic and lymphoid cellsincluding CD4+ T-cells, CD8+ T-cells, CD20+ B-cells, CD56+ NK cells,CD14+ monocytes, as well as granulocytes. IL-2Rγ receptor cDNA isgenerally not found in other cell types, including epithelial cells andfibroblast cells. The expression pattern of this receptor correlateswith the activities of the zalpha11 Ligand and the localization of thezalpha11 receptor. Moreover, antibodies to the IL-2Rγ receptor decreaseor ablate the effect of zalpha11 Ligand in B-cells and BaF3/zalpha11receptor cells, demonstrating that the zalpha11 receptor and IL-2Rγreceptor can heterodimerize in vivo and in vitro.

The zalpha11 Ligand both promotes expansion of NK cell populations frombone marrow and regulates the proliferation of mature T and B cells inresponse to activating stimuli. The zalpha11 Ligand acts through areceptor complex that includes at least one zalpha11 receptor subunitand the γ_(C) subunit of IL2R, even though the cytoplasmic domain ofzalpha11 receptor is capable of transducing signal in a homodimericconfiguration (commonly owned U.S. patent application Ser. No.09/522,217). IL4Rα is also capable of signaling as a homodimer (Kammer,W. et al., J. Biol. Chem. 271:23634-23637, 1996), although the truefunctional IL4 receptor complex is a IL4Rα/γ_(C) heterodimer. Signalingin BaF3/zalpha11 receptor could have resulted from interactions of thehuman zalpha11 receptor with endogenous murine γ_(C), and Examplesherein show that antibodies to the γ_(C) subunit decrease zalpha11Ligand signaling in these cells.

Moreover, the IL2 receptor has been studied in detail and is composed ofan α-β-γ_(C) heterotrimer. The β and γ_(C) subunits are both essentialfor signal transduction and are members of the hematopoietin receptorsuperfamily (Cosman, D., Cytokine 5:95-106, 1993), whereas the α subunitappears to primarily be involved in high-affinity binding conversion andis structurally distinct from the hematopoietin receptor family. Theγ_(C) subunit has been shown to participate in forming the receptors forIL4, IL7, IL9, and IL15, in addition to IL2 (for review, see Sugamura,K., et al., Annu. Rev. Immunol. 14:179-205, 1996), and null mutations inthe γ_(C) gene have been shown to cause X-linked severe combinedimmunodeficiency (X-SCID) (Noguchi, M. et al., Cell 73:147-157, 1993).

Zalpha11 Ligand antagonism of anti-IgM and IL4-induced B cellproliferation (commonly owned U.S. patent application Ser. No.09/522,217, and examples herein) could be due to competition for γ_(C);however, it is clear that IL4 can signal through a γ_(C)-independentreceptor (IL4Rα+IL13Rα′) (Murata, T. et al., Blood 91:3884-3891, 1998).B cells from human SCID patients proliferate normally in response toanti-IgM and IL4 (Matthews, D. J. et al., Blood 85:38-42, 1995), and IL4responsiveness in normal human B cells is associated with both IL13responsiveness and levels of IL13R (Ford, D. et al., J. Immunol.163:3185-3193, 1999). Similarly, Zalpha11 Ligand may signal through aheterodimeric, heterotrimeric or multimeric complex that includeszalpha11 receptor and a non-γ_(C)-subunit. As such, the presentinvention contemplates soluble zalpha11 receptor heterodimericantagonists and binding agents to the zalpha11 Ligand that do notinclude the γ_(C) subunit, but include an additional Class I cytokinesubunit, for example, IL13Rα′ and the like.

The soluble receptors of the present invention are useful as antagonistsof the zalpha11 Ligand cytokine. Such antagonistic effects can beachieved by direct neutralization or binding of the zalpha11 Ligand. Inaddition to antagonistic uses, the soluble receptors of the presentinvention can bind zalpha11 Ligand and act as carrier proteins for thezalpha11 Ligand cytokine, in order to transport the Ligand to differenttissues, organs, and cells within the body. As such, the solublereceptors of the present invention can be fused or coupled to molecules,polypeptides or chemical moieties that direct thesoluble-receptor-Ligand complex to a specific site, such as a tissue,specific immune cell, or tumor. Thus, the soluble receptors of thepresent invention can be used to specifically direct the action of thezalpha11 Ligand. See, Cosman, D. Cytokine 5: 95-106, 1993; andFernandez-Botran, R. Exp. Opin. Invest. Drugs 9:497-513, 2000.

Moreover, the soluble receptors of the present invention can be used tostabilize the zalpha11 Ligand, to increase the bio-availability,therapeutic longevity, and/or efficacy of the Ligand by stabilizing theLigand from degradation or clearance, or by targeting the ligand to asite of action within the body. For example the naturally occurringIL-6/soluble IL-6R complex stabilizes IL-6 and can signal through thegp130 receptor. See, Cosman, D. supra., and Fernandez-Botran, R. supra.

For example, the Zalpha11 Ligand will be useful in treatingtumorgenesis, and therefore would be useful in the treatment of cancer.Zalpha11 Ligand inhibits IL-4 stimulated proliferation of anti-IgMstimulated normal B-cells and a similar effect is observed in B-celltumor lines suggesting that there may be therapeutic benefit in treatingpatients with the zalpha11 Ligand in order to induce the B cell tumorcells into a less proliferative state. The ligand could be administeredin combination with other agents already in use including bothconventional chemotherapeutic agents as well as immune modulators suchas interferon alpha. Alpha/beta interferons have been shown to beeffective in treating some leukemias and animal disease models, and thegrowth inhibitory effects of interferon-alpha and zalpha11 Ligand areadditive for at least one B-cell tumor-derived cell line. Moreover,stabilization of the zalpha11 Ligand or ability to target the Ligand tospecific sites of action with the soluble receptors of the presentinvention would be desirable in this therapeutic endeavor.

The present invention provides a method of reducing proliferation ofneoplastic B or T cells comprising administering to a mammal with a B orT cell neoplasm an amount of a composition of zalpha11 Ligandantagonist, such as the soluble receptors of the present invention,sufficient to reduce proliferation of the neoplastic B or T cells. Inother embodiments, the composition can comprise at least one othercytokine selected from the group consisting of IL-2, IL-15, IL-4,GM-CSF, Flt3 ligand or stem cell factor. Furthermore, the zalpha11Ligand antagonist can be a toxic fusion. Similarly, solublereceptor-toxic fusions and soluble receptors of the present inventioncan be used to reduce proliferation of lymphoid and hematopoieticneoplasms that over-express or grow in response to zalpha11 Ligand.Moreover, indirect effects of the soluble receptors of the presentinvention can modulate NK cell function induced by zalpha11 Ligand, andhence indirectly enhance tumor cell killing.

The present invention provides polynucleotide molecules, including DNAand RNA molecules that encode the heterodimeric zalpha11 receptorpolypeptides disclosed herein. Those skilled in the art will recognizethat, in view of the degeneracy of the genetic code, considerablesequence variation is possible among these polynucleotide molecules. SEQID NO:7 is a degenerate DNA sequence that encompasses all DNAs thatencode the soluble zalpha11 receptor polypeptide of SEQ ID NO:6. SEQ IDNO:66 is a degenerate DNA sequence that encompasses all DNAs that encodethe soluble zalpha11 receptor polypeptide of SEQ ID NO:69. SEQ ID NO:8is a degenerate DNA sequence that encompasses all DNAs that encode thesoluble human IL-2Rγ polypeptide of SEQ ID NO:4. Those skilled in theart will recognize that the degenerate sequence of SEQ ID NO:7, SEQ IDNO:66 and SEQ ID NO:8 also provide all RNA sequences encoding SEQ IDNO:6, SEQ ID NO:69 and SEQ ID NO:4 respectively by substituting U for T.Thus, zalpha11 polypeptide-encoding polynucleotides comprisingnucleotide 1 to nucleotide 654 of SEQ ID NO:7 or comprising nucleotide 1to nucleotide 741 of SEQ ID NO:66, soluble human IL-2Rγpolypeptide-encoding polynucleotides comprising nucleotide 1 tonucleotide 696 of SEQ ID NO:8, and their RNA equivalents arecontemplated by the present invention. Table 1 sets forth the one-lettercodes used within SEQ ID NO:7, SEQ ID NO:66 and SEQ ID NO:8 to denotedegenerate nucleotide positions. “Resolutions” are the nucleotidesdenoted by a code letter. “Complement” indicates the code for thecomplementary nucleotide(s). For example, the code Y denotes either C orT, and its complement R denotes A or G, A being complementary to T, andG being complementary to C.

TABLE 1 Nucleotide Resolution Complement Resolution A A T T C C G G G GC C T T A A R A|G Y C|T Y C|T R A|G M A|C K G|T K G|T M A|C S C|G S C|GW A|T W A|T H A|C|T D A|G|T B C|G|T V A|C|G V A|C|G B C|G|T D A|G|T HA|C|T N A|C|G|T N A|C|G|T

The degenerate codons used in SEQ ID NO:7, SEQ ID NO:66 and SEQ ID NO:8encompass all possible codons for a given amino acid, are set forth inTable 2.

TABLE 2 One Amino Letter Degenerate Acid Code Codons Codon Cys C TGC TGTTGY Ser S AGC AGT TCA TCC TCG TCT WSN Thr T ACA ACC ACG ACT ACN Pro PCCA CCC CCG CCT CCN Ala A GCA GCC GCG GCT GCN Gly G GGA GGC GGG GGT GGNAsn N AAC AAT AAY Asp D GAC GAT GAY Glu E GAA GAG GAR Gln Q CAA CAG CARHis H CAC CAT CAY Arg R AGA AGG CGA CGC CGG CGT MGN Lys K AAA AAG AARMet M ATG ATG Ile I ATA ATC ATT ATH Leu L CTA CTC CTG CTT TTA TTG YTNVal V GTA GTC GTG GTT GTN Phe F TTC TTT TTY Tyr Y TAC TAT TAY Trp W TGGTGG Ter · TAA TAG TGA TRR Asn|Asp B RAY Glu|Gln Z SAR Any X NNN

One of ordinary skill in the art will appreciate that some ambiguity isintroduced in determining a degenerate codon, representative of allpossible codons encoding each amino acid. For example, the degeneratecodon for serine (WSN) can, in some circumstances, encode arginine(AGR), and the degenerate codon for arginine (MGN) can, in somecircumstances, encode serine (AGY). A similar relationship existsbetween codons encoding phenylalanine and leucine. Thus, somepolynucleotides encompassed by the degenerate sequence may encodevariant amino acid sequences, but one of ordinary skill in the art caneasily identify such variant sequences by reference to the amino acidsequence of SEQ ID NO:6, SEQ ID NO:69 or SEQ ID NO:4. Variant sequencescan be readily tested for functionality as described herein.

One of ordinary skill in the art will also appreciate that differentspecies can exhibit “preferential codon usage.” In general, see,Grantham, et al., Nuc. Acids Res. 8:1893-912, 1980; Haas, et al. Curr.Biol. 6:315-24, 1996; Wain-Hobson, et al., Gene 13:355-64, 1981;Grosjean and Fiers, Gene 18:199-209, 1982; Holm, Nuc. Acids Res.14:3075-87, 1986; Ikemura, J. Mol. Biol. 158:573-97, 1982. As usedherein, the term “preferential codon usage” or “preferential codons” isa term of art referring to protein translation codons that are mostfrequently used in cells of a certain species, thus favoring one or afew representatives of the possible codons encoding each amino acid (SeeTable 2). For example, the amino acid Threonine (Thr) may be encoded byACA, ACC, ACG, or ACT, but in mammalian cells ACC is the most commonlyused codon; in other species, for example, insect cells, yeast, virusesor bacteria, different Thr codons may be preferential. Preferentialcodons for a particular species can be introduced into thepolynucleotides of the present invention by a variety of methods knownin the art. Introduction of preferential codon sequences intorecombinant DNA can, for example, enhance production of the protein bymaking protein translation more efficient within a particular cell typeor species. Therefore, the degenerate codon sequence disclosed in SEQ IDNO:7, SEQ ID NO:66 and SEQ ID NO:8 serves as a template for optimizingexpression of polynucleotides and polypeptides in various cell types andspecies commonly used in the art and disclosed herein. Sequencescontaining preferential codons can be tested and optimized forexpression in various species, and tested for functionality as disclosedherein.

Within preferred embodiments of the invention the isolatedpolynucleotides will hybridize to similar sized regions of SEQ ID NO:5,SEQ ID NO:68 or SEQ ID NO:3, or a sequence complementary thereto, understringent conditions. In general, stringent conditions are selected tobe about 5° C. lower than the thermal melting point (T_(m)) for thespecific sequence at a defined ionic strength and pH. The T_(m) is thetemperature (under defined ionic strength and pH) at which 50% of thetarget sequence hybridizes to a perfectly matched probe. Numerousequations for calculating T_(m) are known in the art, and are specificfor DNA, RNA and DNA-RNA hybrids and polynucleotide probe sequences ofvarying length (see, for example, Sambrook et al., Molecular Cloning: ALaboratory Manual, Second Edition (Cold Spring Harbor Press 1989);Ausubel et al., (eds.), Current Protocols in Molecular Biology (JohnWiley and Sons, Inc. 1987); Berger and Kimmel (eds.), Guide to MolecularCloning Techniques (Academic Press, Inc. 1987); and Wetmur, Crit. Rev.Biochem. Mol. Biol. 26:227 (1990)). Sequence analysis software such asOLIGO 6.0 (LSR; Long Lake, Minn.) and Primer Premier 4.0 (PremierBiosoft International; Palo Alto, Calif.), as well as sites on theInternet, are available tools for analyzing a given sequence andcalculating T_(m) based on user-defined criteria. Such programs can alsoanalyze a given sequence under defined conditions and identify suitableprobe sequences. Typically, hybridization of longer polynucleotidesequences (e.g., >50 base pairs) is performed at temperatures of about20-25° C. below the calculated T_(m). For smaller probes (e.g., <50 basepairs) hybridization is typically carried out at the T_(m) or 5-10° C.below. This allows for the maximum rate of hybridization for DNA-DNA andDNA-RNA hybrids. Higher degrees of stringency at lower temperatures canbe achieved with the addition of formamide which reduces the T_(m) ofthe hybrid about 1° C. for each 1% formamide in the buffer solution.Suitable stringent hybridization conditions are equivalent to about a 5h to overnight incubation at about 42° C. in a solution comprising:about 40-50% formamide, up to about 6×SSC, about 5×Denhardt's solution,zero up to about 10% dextran sulfate, and about 10-20 μg/ml denaturedcommercially-available carrier DNA. Generally, such stringent conditionsinclude temperatures of 20-70° C. and a hybridization buffer containingup to 6×SSC and 0-50% formamide; hybridization is then followed bywashing filters in up to about 2×SSC. For example, a suitable washstringency is equivalent to 0.1×SSC to 2×SSC, 0.1% SDS, at 55° C. to 65°C. Different degrees of stringency can be used during hybridization andwashing to achieve maximum specific binding to the target sequence.Typically, the washes following hybridization are performed atincreasing degrees of stringency to remove non-hybridized polynucleotideprobes from hybridized complexes. Stringent hybridization and washconditions depend on the length of the probe, reflected in the Tm,hybridization and wash solutions used, and are routinely determinedempirically by one of skill in the art.

As previously noted, the isolated polynucleotides of the presentinvention include DNA and RNA. Methods for preparing DNA and RNA arewell known in the art. In general, RNA is isolated from a tissue or cellthat produces large amounts of zalpha11 receptor RNA or the RNA for theheterodimeric component of the receptor, such as IL-2Rγ, or other classI cytokine receptor. Such tissues and cells are identified by Northernblotting (Thomas, Proc. Natl. Acad. Sci. USA 77:5201, 1980), and includePBLs, spleen, thymus, and lymph tissues, Raji cells, humanerythroleukemia cell lines (e.g., TF-1), acute monocytic leukemia celllines, other lymphoid and hematopoietic cell lines, and the like, forthe zalpha11 receptor. RNA for a heterodimeric component of thereceptor, such as IL-2Rγ, or other class I cytokine receptor can beisolated from lymphoid cells, such as those described above, and othercells and tissues as is known in the art for these receptors. Total RNAcan be prepared using guanidinium isothiocyanate extraction followed byisolation by centrifugation in a CsCl gradient (Chirgwin et al.,Biochemistry 18:52-94, 1979). Poly (A)⁺ RNA is prepared from total RNAusing the method of Aviv and Leder (Proc. Natl. Acad. Sci. USA69:1408-12, 1972). Complementary DNA (cDNA) is prepared from poly(A)⁺RNA using known methods. In the alternative, genomic DNA can beisolated. Polynucleotides encoding zalpha11 polypeptides are thenidentified and isolated by, for example, hybridization or polymerasechain reaction (PCR) (Mullis, U.S. Pat. No. 4,683,202).

The polynucleotides of the present invention can also be synthesizedusing DNA synthesis machines. Currently the method of choice is thephosphoramidite method. If chemically synthesized double stranded DNA isrequired for an application such as the synthesis of a gene or a genefragment, then each complementary strand is made separately. Theproduction of short polynucleotides (60 to 80 bp) is technicallystraightforward and can be accomplished by synthesizing thecomplementary strands and then annealing them. However, for producinglonger polynucleotides (>300 bp), special strategies are usuallyemployed, because the coupling efficiency of each cycle during chemicalDNA synthesis is seldom 100%. To overcome this problem, synthetic genes(double-stranded) are assembled in modular form from single-strandedfragments that are from 20 to 100 nucleotides in length.

An alternative way to prepare a full-length gene is to synthesize aspecified set of overlapping oligonucleotides (40 to 100 nucleotides).After the 3′ and 5′ short overlapping complementary regions (6 to 10nucleotides) are annealed, large gaps still remain, but the shortbase-paired regions are both long enough and stable enough to hold thestructure together. The gaps are filled and the DNA duplex is completedvia enzymatic DNA synthesis by E. coli DNA polymerase I. After theenzymatic synthesis is completed, the nicks are sealed with T4 DNAligase. Double-stranded constructs are sequentially linked to oneanother to form the entire gene sequence which is verified by DNAsequence analysis. See Glick and Pasternak, Molecular Biotechnology,Principles & Applications of Recombinant DNA, (ASM Press, Washington,D.C. 1994); Itakura et al., Annu. Rev. Biochem. 53: 323-56, 1984 andClimie et al., Proc. Natl. Acad. Sci. USA 87:633-7, 1990. Moreover,other sequences are generally added that contain signals for properinitiation and termination of transcription and translation.

The present invention further provides counterpart polypeptides andpolynucleotides from other species (orthologs). These species include,but are not limited to mammalian, avian, amphibian, reptile, fish,insect and other vertebrate and invertebrate species. Of particularinterest are heterodimeric soluble receptor complexes combining solublezalpha11 receptor and soluble human IL-2Rγ or other soluble Class Icytokine receptor polypeptides from other mammalian species, includingmurine, porcine, ovine, bovine, canine, feline, equine, and otherprimate polypeptides. Known and unknown orthologs of human solublezalpha11 receptor and soluble human IL-2Rγ or other soluble Class Icytokine receptors can be cloned using information and compositionsprovided by the present invention in combination with conventionalcloning techniques. For example, a cDNA can be cloned using mRNAobtained from a tissue or cell type, such as lymphoid cells, thatexpresses zalpha11 receptor, human IL-2Rγ or other Class I cytokinereceptors. Moreover, suitable sources of mRNA can be identified byprobing Northern blots with probes designed from the sequences disclosedherein. A library is then prepared from mRNA of a positive tissue orcell line. A zalpha11-encoding cDNA can then be isolated by a variety ofmethods, such as by probing with a complete or partial human cDNA orwith one or more sets of degenerate probes based on the disclosedsequences. A cDNA can also be cloned using PCR (Mullis, supra.), usingprimers designed from the representative human zalpha11 sequence, orsoluble human IL-2Rγ sequence, disclosed herein. Within an additionalmethod, the cDNA library can be used to transform or transfect hostcells, and expression of the cDNA of interest can be detected with anantibody to zalpha11 polypeptide. Similar techniques can also be appliedto the isolation of genomic clones.

Cytokine receptor subunits are characterized by a multi-domain structurecomprising an extracellular domain, a transmembrane domain that anchorsthe polypeptide in the cell membrane, and an intracellular domain. Theextracellular domain the zalpha11 receptor is a ligand-binding domain,that binds zalpha11 Ligand, and the intracellular domain is an effectordomain involved in signal transduction, although ligand-binding andeffector functions can reside on separate subunits of a multimericreceptor. The ligand-binding domain may itself be a multi-domainstructure. Multimeric receptors include homodimers (e.g., PDGF receptorαα and ββ isoforms, erythropoietin receptor, MPL, and G-CSF receptor),heterodimers whose subunits each have ligand-binding and effectordomains (e.g., PDGF receptor αβ isoform), and multimers having componentsubunits with disparate functions (e.g., IL-2, IL-3, IL-4, IL-5, IL-6,IL-7, IL-13, IL-15 and GM-CSF receptors). Some receptor subunits arecommon to a plurality of receptors. For example, the AIC2B subunit,which cannot bind ligand on its own but includes an intracellular signaltransduction domain, is a component of IL-3 and GM-CSF receptors. Manycytokine receptors can be placed into one of four related families onthe basis of the structure and function. Hematopoietic receptors, forexample, are characterized by the presence of a domain containingconserved cysteine residues and the WSXWS motif (SEQ ID NO:13). Cytokinereceptor structure has been reviewed by Urdal, Ann. Reports Med. Chem.26:221-228, 1991; and Cosman, Cytokine 5:95-106, 1993. Under selectivepressure for organisms to acquire new biological functions, new receptorfamily members likely arise from duplication of existing receptor genesleading to the existence of multi-gene families. Family members thuscontain vestiges of the ancestral gene, and these characteristicfeatures can be exploited in the isolation and identification ofadditional family members. Thus, the cytokine receptor superfamily issubdivided into several families, for example, the immunoglobulin family(including CSF-1, MGF, IL-1, and PDGF receptors); the hematopoietinfamily (including IL-2 receptor β-subunit, GM-CSF receptor α-subunit,GM-CSF receptor β-subunit; and G-CSF, EPO, IL-3, IL-4, IL-5, IL-6, IL-7,IL-9, IL-13 and IL-15 receptors); TNF receptor family (including TNF(p80) TNF (p60) receptors, CD27, CD30, CD40, Fas, and NGF receptor).

Analysis of the zalpha11 receptor sequence suggests that it is a memberof the same receptor subfamily as the IL-2 receptor β-subunit, IL-4, andIL-9, receptors. Certain receptors in this subfamily (e.g., EPO-R orMPL) associate to form homodimers that transduce a signal. Other membersof the subfamily (e.g., IL-6, IL-11, and LIF receptors) combine with asecond subunit (termed a β-subunit) to bind ligand and transduce asignal. Specific β-subunits associate with a plurality of specificcytokine receptor subunits. For example, the β-subunit gp130 (Hibi etal., Cell 63:1149-1157, 1990) associates with receptor subunits specificfor IL-6, IL-11, and LIF (Gearing et al., EMBO J. 10:2839-2848, 1991;Gearing et al., U.S. Pat. No. 5,284,755). Oncostatin M binds to aheterodimer of LIF receptor and gp130. CNTF binds to trimeric receptorscomprising CNTF receptor, LIF receptor, and gp130 subunits. Moreover,IL-4 and IL-13 elicit responses through the IL-4 and IL-13 receptors byacting upon various functional heterodimeric receptor complexes, e.g.with and without the γ_(C) subunit, and such heterodimeric receptorcomplexes may affect whether the cytokines act upon hematopoietic ornon-hematopoietic cells (Andersson, A. et al., Eur. J. Immunol.27:1762-1768, 1997; Murata, T. et al., Blood 10:3884-3891, 1998).Moreover, binding affinity of IL-4 on its receptor is increased when theγ_(C) subunit of the IL4R complex is replaced by an IL-13Rα′ subunit(Murata, T. et al., supra.). Thus, the soluble receptors of the presentinvention include zalpha11 receptor homodimers; and heterodimers thathave a zalpha11 receptor component, such as soluble zalpha11/IL-2Rγ orsoluble zalpha11 receptor heterodimerized with another soluble Class Icytokine receptor, such as IL-13Rα (SEQ ID NO:84), IL-13Rα′ (SEQ IDNO:82) or an IL-15 (SEQ ID NO:86) receptor subunit.

For example, suitable Class I cytokine soluble receptors that canheterodimerize with a soluble zalpha11 receptor component (e.g., SEQ IDNO:6), include a soluble receptor for IL-13Rα as shown in SEQ ID NO:84,IL-13Rα′ as shown in SEQ ID NO:82, or IL-15 as shown in SEQ ID NO:86.Moreover, functional sub-fragments, such as minimal cytokine bindingfragments, of these Class I cytokine soluble receptors can be used. Suchfunctional fragments include 1 to 322, 7 to 322, and 105 to 322 of SEQID NO:82; 1 to 317, 10 to 317, and 105 to 317 of SEQ ID NO:84; and 1 to173 of SEQ ID NO:86. The corresponding polynucleotide sequences are asshown in SEQ ID NO:81, SEQ ID NO:83 and SEQ ID NO:85 respecitvels. It iswell within the level of one of skill in the art to delineate whatsequences of a known class I cytokine sequence comprise theextracellular cytokine binding domain free of a transmembrane domain andintracellular domain.

A polynucleotide sequence for the mouse ortholog of human zalpha11receptor has been identified and is shown in SEQ ID NO:11 and thecorresponding amino acid sequence shown in SEQ ID NO:12. Analysis of themouse zalpha11 polypeptide encoded by the DNA sequence of SEQ ID NO:11revealed an open reading frame encoding 529 amino acids (SEQ ID NO:12)comprising a predicted secretory signal peptide of 19 amino acidresidues (residue 1 (Met) to residue 19 (Ser) of SEQ ID NO:12), and amature polypeptide of 510 amino acids (residue 20 (Cys) to residue 529(Ser) of SEQ ID NO:2). In addition to the WSXWS motif (SEQ ID NO:13)corresponding to residues 214 to 218 of SEQ ID NO:12, the receptorcomprises a cytokine-binding domain of approximately 200 amino acidresidues (residues 20 (Cys) to 237 (His) of SEQ ID NO:12); a domainlinker (residues 120 (Pro) to 123 (Pro) of SEQ ID NO:12); a penultimatestrand region (residues 192 (Lys) to 202 (Ala) of SEQ ID NO:12); atransmembrane domain (residues 238 (Met) to 254 (Leu) of SEQ ID NO:12);complete intracellular signaling domain (residues 255 (Lys) to 529 (Ser)of SEQ ID NO:12) which contains a “Box I” signaling site (residues 266(Ile) to 273 (Pro) of SEQ ID NO:12), and a “Box II” signaling site(residues 301 (Ile) to 304 (Val) of SEQ ID NO:2). A comparison of thehuman and mouse amino acid sequences reveals that both the human andorthologous polypeptides contain corresponding structural featuresdescribed above. The mature sequence for the mouse zalpha11 begins atCys₂₀ (as shown in SEQ ID NO:12), which corresponds to Cys₂₀ (as shownin SEQ ID NO:2) in the human sequence. There is about 69% identity abetween the mouse and human zalpha11 sequences over the extracellularcytokine binding domain corresponding to residues 20 (Cys) to 237 (His)of SEQ ID NO:2 (SEQ ID NO:6) and residues 20 (Cys) to 237 (His) of SEQID NO:12. The above percent identities were determined using a FASTAprogram with ktup=1, gap opening penalty=12, gap extension penalty=2,and substitution matrix=BLOSUM62, with other FASTA program parametersset as default. The corresponding polynucleotides encoding the mousezalpha11 polypeptide regions, domains, motifs, residues and sequencesdescribed above are as shown in SEQ ID NO:11.

The present invention also provides for a heterodimeric solublereceptor, wherein the isolated soluble zalpha11 receptor polypeptidetherein is substantially similar to the polypeptides of SEQ ID NO:6 andtheir orthologs. Moreover, in a preferred embodiment, the presentinvention also provides for a heterodimeric soluble receptor, wherein anisolated soluble IL-2Rγ receptor polypeptide therein is substantiallysimilar to the polypeptides of SEQ ID NO:4 and their orthologs. The term“substantially similar” is used herein to denote polypeptides having atleast 70%, more preferably at least 80%, sequence identity to thesequences shown in SEQ ID NO:6 or their orthologs. Such polypeptideswill more preferably be at least 90% identical, and most preferably 95%or more identical to SEQ ID NO:6 or SEQ ID NO:4 their orthologs.)Percent sequence identity is determined by conventional methods. See,for example, Altschul et al., Bull. Math. Bio. 48: 603-616, 1986 andHenikoff and Henikoff, Proc. Natl. Acad. Sci. USA 89:10915-10919, 1992.Briefly, two amino acid sequences are aligned to optimize the alignmentscores using a gap opening penalty of 10, a gap extension penalty of 1,and the “blosum 62” scoring matrix of Henikoff and Henikoff (ibid.) asshown in Table 3 (amino acids are indicated by the standard one-lettercodes). The percent identity is then calculated as:

$\frac{{Total}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{identical}\mspace{14mu}{matches}}{\begin{bmatrix}{{length}\mspace{14mu}{of}\mspace{14mu}{the}\mspace{14mu}{longer}\mspace{14mu}{sequences}\mspace{14mu}{plus}\mspace{14mu}{the}} \\{{number}\mspace{14mu}{of}\mspace{14mu}{gaps}\mspace{14mu}{introduced}\mspace{14mu}{into}\mspace{14mu}{longer}} \\{{sequence}\mspace{14mu}{in}\mspace{14mu}{order}\mspace{14mu}{to}\mspace{14mu}{align}\mspace{14mu}{the}\mspace{14mu}{two}\mspace{14mu}{sequences}}\end{bmatrix}} \times 100$

TABLE 3 A R N D C Q E G H I L K M F P S T W Y V A 4 R −1 5 N −2 0 6 D −2−2 1 6 C 0 −3 −3 −3 9 Q −1 1 0 0 −3 5 E −1 0 0 2 −4 2 5 G 0 −2 0 −1 −3−2 −2 6 H −2 0 1 −1 −3 0 0 −2 8 I −1 −3 −3 −3 −1 −3 −3 −4 −3 4 L −1 −2−3 −4 −1 −2 −3 −4 −3 2 4 K −1 2 0 −1 −3 1 1 −2 −1 −3 −2 5 M −1 −1 −2 −3−1 0 −2 −3 −2 1 2 −1 5 F −2 −3 −3 −3 −2 −3 −3 −3 −1 0 0 −3 0 6 P −1 −2−2 −1 −3 −1 −1 −2 −2 −3 −3 −1 −2 −4 7 S 1 −1 1 0 −1 0 0 0 −1 −2 −2 0 −1−2 −1 4 T 0 −1 0 −1 −1 −1 −1 −2 −2 −1 −1 −1 −1 −2 −1 1 5 W −3 −3 −4 −4−2 −2 −3 −2 −2 −3 −2 −3 −1 1 −4 −3 −2 11 Y −2 −2 −2 −3 −2 −1 −2 −3 −2 −1−1 −2 −1 3 −3 −2 −2 2 7 V 0 −3 −3 −3 −1 −2 −2 −3 −3 3 1 −2 1 −1 −2 −2 0−3 −1 4

Sequence identity of polynucleotide molecules is determined by similarmethods using a ratio as disclosed above.

Those skilled in the art appreciate that there are many establishedalgorithms available to align two amino acid sequences. The “FASTA”similarity search algorithm of Pearson and Lipman is a suitable proteinalignment method for examining the level of identity shared by an aminoacid sequence disclosed herein and the amino acid sequence of a putativevariant zsig57. The FASTA algorithm is described by Pearson and Lipman,Proc. Nat'l Acad. Sci. USA 85:2444 (1988), and by Pearson, Meth.Enzymol. 183:63 (1990).

Briefly, FASTA first characterizes sequence similarity by identifyingregions shared by the query sequence (e.g., SEQ ID NO:6) and a testsequence that have either the highest density of identities (if the ktupvariable is 1) or pairs of identities (if ktup=2), without consideringconservative amino acid substitutions, insertions, or deletions. The tenregions with the highest density of identities are then rescored bycomparing the similarity of all paired amino acids using an amino acidsubstitution matrix, and the ends of the regions are “trimmed” toinclude only those residues that contribute to the highest score. Ifthere are several regions with scores greater than the “cutoff” value(calculated by a predetermined formula based upon the length of thesequence and the ktup value), then the trimmed initial regions areexamined to determine whether the regions can be joined to form anapproximate alignment with gaps. Finally, the highest scoring regions ofthe two amino acid sequences are aligned using a modification of theNeedleman-Wunsch-Sellers algorithm (Needleman and Wunsch, J. Mol. Biol.48:444 (1970); Sellers, SIAM J. Appl. Math. 26:787 (1974)), which allowsfor amino acid insertions and deletions. Preferred program parametersfor FASTA analysis are: ktup=1, gap opening penalty=10, gap extensionpenalty=1, and substitution matrix=BLOSUM62, with other parameters setas default. These FASTA program parameters can be introduced into aFASTA program by modifying the scoring matrix file (“SMATRIX”), asexplained in Appendix 2 of Pearson, Meth. Enzymol. 183:63 (1990).

FASTA can also be used to determine the sequence identity of nucleicacid molecules using a ratio as disclosed above. For nucleotide sequencecomparisons, the ktup value can range between one to six, preferablyfrom three to six, most preferably three, with other program parametersset as default.

The BLOSUM62 table (Table 3) is an amino acid substitution matrixderived from about 2,000 local multiple alignments of protein sequencesegments, representing highly conserved regions of more than 500 groupsof related proteins (Henikoff and Henikoff, Proc. Nat'l Acad. Sci. USA89:10915 (1992)). Accordingly, the BLOSUM62 substitution frequencies canbe used to define conservative amino acid substitutions that may beintroduced into the amino acid sequences of the present invention.Although it is possible to design amino acid substitutions based solelyupon chemical properties (as discussed below), the language“conservative amino acid substitution” preferably refers to asubstitution represented by a BLOSUM62 value of greater than −1. Forexample, an amino acid substitution is conservative if the substitutionis characterized by a BLOSUM62 value of 0, 1, 2, or 3. According to thissystem, preferred conservative amino acid substitutions arecharacterized by a BLOSUM62 value of at least 1 (e.g., 1, 2 or 3), whilemore preferred conservative amino acid substitutions are characterizedby a BLOSUM62 value of at least 2 (e.g., 2 or 3).

Variant zalpha11 polypeptides or substantially homologous zalpha11polypeptides are characterized as having one or more amino acidsubstitutions, deletions or additions. These changes are preferably of aminor nature, that is conservative amino acid substitutions (see Table4) and other substitutions that do not significantly affect the foldingor activity of the polypeptide; small deletions, typically of one toabout 30 amino acids; and small amino- or carboxyl-terminal extensions,such as an amino-terminal methionine residue, a small linker peptide ofup to about 20-25 residues, or an affinity tag. The present inventionthus includes zalpha11 soluble receptor polypeptides of from about 190to about 245 amino acid residues that comprise a sequence that is atleast 80%, preferably at least 90%, and more preferably 95% or moreidentical to the corresponding region of SEQ ID NO:6. Polypeptidescomprising affinity tags can further comprise a proteolytic cleavagesite between the zalpha11 polypeptide and the affinity tag. Suitablesites include thrombin cleavage sites and factor Xa cleavage sites.

TABLE 4 Conservative amino acid substitutions Basic: arginine lysinehistidine Acidic: glutamic acid aspartic acid Polar: glutamineasparagine Hydrophobic: leucine isoleucine valine Aromatic:phenylalanine tryptophan tyrosine Small: glycine alanine serinethreonine methionine

The present invention further provides a variety of other polypeptidefusions and related multimeric proteins comprising one or morepolypeptide fusions. For example, a soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ canbe prepared as a fusion to a dimerizing protein as disclosed in U.S.Pat. Nos. 5,155,027 and 5,567,584. Preferred dimerizing proteins in thisregard include immunoglobulin constant region domains, e.g., IgGγ1, andthe human κ light chain. Immunoglobulin-soluble zalpha11 receptor orimmunoglobulin-soluble zalpha11 heterodimeric polypeptide, such asimmunoglobulin-soluble zalpha11/IL-2Rγ fusions can be expressed ingenetically engineered cells to produce a variety of multimeric zalpha11receptor analogs. Auxiliary domains can be fused to soluble zalpha11receptor or soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ to target them to specific cells, tissues, ormacromolecules (e.g., collagen, or cells expressing the zalpha11Ligand). A zalpha11 polypeptide can be fused to two or more moieties,such as an affinity tag for purification and a targeting domain.Polypeptide fusions can also comprise one or more cleavage sites,particularly between domains. See, Tuan et al., Connective TissueResearch 34:1-9, 1996.

The proteins of the present invention can also comprise non-naturallyoccurring amino acid residues. Non-naturally occurring amino acidsinclude, without limitation, trans-3-methylproline, 2,4-methanoproline,cis-4-hydroxyproline, trans-4-hydroxyproline, N-methylglycine,allo-threonine, methylthreonine, hydroxyethylcysteine,hydroxyethylhomocysteine, nitroglutamine, homoglutamine, pipecolic acid,thiazolidine carboxylic acid, dehydroproline, 3- and 4-methylproline,3,3-dimethylproline, tert-leucine, norvaline, 2-azaphenylalanine,3-azaphenylalanine, 4-azaphenylalanine, and 4-fluorophenylalanine.Several methods are known in the art for incorporating non-naturallyoccurring amino acid residues into proteins. For example, an in vitrosystem can be employed wherein nonsense mutations are suppressed usingchemically aminoacylated suppressor tRNAs. Methods for synthesizingamino acids and aminoacylating tRNA are known in the art. Transcriptionand translation of plasmids containing nonsense mutations is carried outin a cell-free system comprising an E. coli S30 extract and commerciallyavailable enzymes and other reagents. Proteins are purified bychromatography. See, for example, Robertson et al., J. Am. Chem. Soc.113:2722, 1991; Ellman et al., Methods Enzymol. 202:301, 1991; Chung etal., Science 259:806-9, 1993; and Chung et al., Proc. Natl. Acad. Sci.USA 90:10145-9, 1993). In a second method, translation is carried out inXenopus oocytes by microinjection of mutated mRNA and chemicallyaminoacylated suppressor tRNAs (Turcatti et al., J. Biol. Chem.271:19991-8, 1996). Within a third method, E. coli cells are cultured inthe absence of a natural amino acid that is to be replaced (e.g.,phenylalanine) and in the presence of the desired non-naturallyoccurring amino acid(s) (e.g., 2-azaphenylalanine, 3-azaphenylalanine,4-azaphenylalanine, or 4-fluorophenylalanine). The non-naturallyoccurring amino acid is incorporated into the protein in place of itsnatural counterpart. See, Koide et al., Biochem. 33:7470-7476, 1994.Naturally occurring amino acid residues can be converted tonon-naturally occurring species by in vitro chemical modification.Chemical modification can be combined with site-directed mutagenesis tofurther expand the range of substitutions (Wynn and Richards, ProteinSci. 2:395-403, 1993).

A limited number of non-conservative amino acids, amino acids that arenot encoded by the genetic code, non-naturally occurring amino acids,and unnatural amino acids may be substituted for zalpha11 amino acidresidues.

Essential amino acids in the polypeptides of the present invention canbe identified according to procedures known in the art, such assite-directed mutagenesis or alanine-scanning mutagenesis (Cunninghamand Wells, Science 244: 1081-5, 1989; Bass et al., Proc. Natl. Acad.Sci. USA 88:4498-502, 1991). In the latter technique, single alaninemutations are introduced at every residue in the molecule, and theresultant mutant molecules are tested for biological activity (e.g.ligand binding and signal transduction) as disclosed below to identifyamino acid residues that are critical to the activity of the molecule.See also, Hilton et al., J. Biol. Chem. 271:4699-4708, 1996. Sites ofligand-receptor, protein-protein or other biological interaction canalso be determined by physical analysis of structure, as determined bysuch techniques as nuclear magnetic resonance, crystallography, electrondiffraction or photoaffinity labeling, in conjunction with mutation ofputative contact site amino acids. See, for example, de Vos et al.,Science 255:306-312, 1992; Smith et al., J. Mol. Biol. 224:899-904,1992; Wlodaver et al., FEBS Lett. 309:59-64, 1992. The identities ofessential amino acids can also be inferred from analysis of homologieswith related receptors.

Determination of amino acid residues that are within regions or domainsthat are critical to maintaining structural integrity can be determined.Within these regions one can determine specific residues that will bemore or less tolerant of change and maintain the overall tertiarystructure of the molecule. Methods for analyzing sequence structureinclude, but are not limited to, alignment of multiple sequences withhigh amino acid or nucleotide identity and computer analysis usingavailable software (e.g., the Insight II® viewer and homology modelingtools; MSI, San Diego, Calif.), secondary structure propensities, binarypatterns, complementary packing and buried polar interactions (Barton,Current Opin. Struct. Biol. 5:372-376, 1995; and, Cordes et al., CurrentOpin. Struct. Biol. 6:3-10, 1996). In general, when designingmodifications to molecules or identifying specific fragmentsdetermination of structure will be accompanied by evaluating activity ofmodified molecules.

Amino acid sequence changes are made in soluble zalpha11 receptor orsoluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ, so as to minimize disruption of higher order structureessential to biological activity. For example, where the solublezalpha11 receptor or soluble zalpha11 heterodimeric polypeptide, such assoluble zalpha11/IL-2Rγ comprises one or more helices, changes in aminoacid residues will be made so as not to disrupt the helix geometry andother components of the molecule where changes in conformation abatesome critical function, for example, binding of the molecule to thezalpha11 Ligand, or antagonizing zalpha11 Ligand activity. The effectsof amino acid sequence changes can be predicted by, for example,computer modeling as disclosed above or determined by analysis ofcrystal structure (see, e.g., Lapthorn et al., Nat. Struct. Biol.2:266-268, 1995). Other techniques that are well known in the artcompare folding of a variant protein to a standard molecule (e.g., thenative protein). For example, comparison of the cysteine pattern in avariant and standard molecules can be made. Mass spectrometry andchemical modification using reduction and alkylation provide methods fordetermining cysteine residues which are associated with disulfide bondsor are free of such associations (Bean et al., Anal. Biochem.201:216-226, 1992; Gray, Protein Sci. 2:1732-1748, 1993; and Pattersonet al., Anal. Chem. 66:3727-3732, 1994). It is generally believed thatif a modified molecule does not have the same disulfide bonding patternas the standard molecule folding would be affected. Another well knownand accepted method for measuring folding is circular dichrosism (CD).Measuring and comparing the CD spectra generated by a modified moleculeand standard molecule is routine (Johnson, Proteins 7:205-214, 1990).Crystallography is another well known method for analyzing folding andstructure. Nuclear magnetic resonance (NMR), digestive peptide mappingand epitope mapping are also known methods for analyzing folding andstructural similarities between proteins and polypeptides (Schaanan etal., Science 257:961-964, 1992).

A Hopp/Woods hydrophilicity profile of the zalpha11 protein sequence asshown in SEQ ID NO:6 can be generated (Hopp et al., Proc. Natl. Acad.Sci. 78:3824-3828, 1981; Hopp, J. Immun. Meth. 88:1-18, 1986 andTriquier et al., Protein Engineering 11:153-169, 1998). The profile isbased on a sliding six-residue window. Buried G, S, and T residues andexposed H, Y, and W residues were ignored. For example, in the solublezalpha11 receptor, hydrophilic regions include amino acid residues 55through 60 of SEQ ID NO: 2, amino acid residues 56 through 61 of SEQ IDNO: 2, amino acid residues 139 through 144 of SEQ ID NO: 2, and aminoacid residues 227 through 232 of SEQ ID NO: 2. The correspondinghydrophilic regions in reference to SEQ ID NO:6 can be made withcross-reference to the above amino acid residues of SEQ ID NO:2.

Those skilled in the art will recognize that hydrophilicity orhydrophobicity will be taken into account when designing modificationsin the amino acid sequence of a soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ, soas not to disrupt the overall structural and biological profile. Ofparticular interest for replacement are hydrophobic residues selectedfrom the group consisting of Val, Leu and Ile or the group consisting ofMet, Gly, Ser, Ala, Tyr and Trp. For example, residues tolerant ofsubstitution could include such residues as shown in SEQ ID NO:6, SEQ IDNO:69 and SEQ ID NO:4. However, Cysteine residues could be relativelyintolerant of substitution.

The identities of essential amino acids can also be inferred fromanalysis of sequence similarity between Class I cytokine receptor familymembers with soluble zalpha11 receptor or soluble IL-2Rγ receptor. Usingmethods such as “FASTA” analysis described previously, regions of highsimilarity are identified within a family of proteins and used toanalyze amino acid sequence for conserved regions. An alternativeapproach to identifying a variant extracellular domain zalpha11polynucleotide on the basis of structure is to determine whether anucleic acid molecule encoding a potential variant zalpha11polynucleotide can hybridize to a nucleic acid molecule having thenucleotide sequence of SEQ ID NO:5, or SEQ ID NO:68 as discussed above.Likewise, variants of soluble class I cytokine receptor contained withina zalpha11 heterodimeric polypeptide, such as the soluble IL-2Rγreceptor component in soluble zalpha11/IL-2Rγ, can be identified asdescribed above.

Other methods of identifying essential amino acids in the polypeptidesof the present invention are procedures known in the art, such assite-directed mutagenesis or alanine-scanning mutagenesis (Cunninghamand Wells, Science 244:1081 (1989), Bass et al., Proc. Natl Acad. Sci.USA 88:4498 (1991), Coombs and Corey, “Site-Directed Mutagenesis andProtein Engineering,” in Proteins: Analysis and Design, Angeletti (ed.),pages 259-311 (Academic Press, Inc. 1998)). In the latter technique,single alanine mutations are introduced at every residue in themolecule, and the resultant mutant molecules are tested for biologicalactivity as disclosed below to identify amino acid residues that arecritical to the activity of the molecule. See also, Hilton et al., J.Biol Chem. 271:4699 (1996).

The present invention also includes functional fragments of solublezalpha11 receptor polypeptides or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ polypeptides and nucleicacid molecules encoding such functional fragments. A “functional”soluble zalpha11 receptor polypeptide or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ polypeptide, or fragmentthereof defined herein is characterized by its by its ability to bind toan anti-zalpha11 antibody, or to zalpha11 Ligand (either soluble orimmobilized), or to antagonize zalpha11 Ligand activity in, for example,a biological or binding assay. As previously described herein, zalpha11receptor is characterized by a class I cytokine receptor structure.Thus, the present invention further provides fusion proteinsencompassing: (a) homodimeric or multimeric polypeptide moleculescomprising an extracellular domain described herein; and (b) functionalfragments comprising one or more of these domains. The other polypeptideportion of the fusion protein may be contributed by another class Icytokine receptor, for example, IL-2Rγ, IL-2 receptor β-subunit and theβ-common receptor (i.e., IL3, IL-5, and GM-CSF receptor β-subunits),IL-13α, IL-13α′, or IL-15 receptor subunits, or by a non-native and/oran unrelated secretory signal peptide that facilitates secretion of thesoluble fusion protein.

Routine deletion analyses of nucleic acid molecules can be performed toobtain functional fragments of a nucleic acid molecule that encode asoluble zalpha11 receptor or soluble zalpha11 heterodimeric polypeptide,such as soluble zalpha11/IL-2Rγ. As an illustration, DNA moleculeshaving the nucleotide sequence of SEQ ID NO:1 or fragments thereof, canbe digested with Bal31 nuclease to obtain a series of nested deletions.These DNA fragments are then inserted into expression vectors in properreading frame, and the expressed polypeptides are isolated and testedfor antagonizing zalpha11 Ligand biological or zalpha11 Ligand bindingactivity; or for the ability to bind anti-soluble zalpha11 receptor oranti-soluble zalpha11 heterodimeric polypeptide antibodies; or for theability to bind zalpha11 Ligand. One alternative to exonucleasedigestion is to use oligonucleotide-directed mutagenesis to introducedeletions or stop codons to specify production of a desired polypeptidefragment. Alternatively, particular fragments of a soluble zalpha11receptor or soluble zalpha11 heterodimeric polypeptide polynucleotidecan be synthesized using the polymerase chain reaction.

Standard methods for identifying functional domains, such as Ligandbinding domains, are routine for those of skill in the art. For example,studies on the truncation at either or both termini of interferons havebeen summarized by Horisberger and Di Marco, Pharmac. Ther. 66:507(1995). Moreover, standard techniques for functional analysis ofproteins are described by, for example, Treuter et al., Molec. Gen.Genet. 240:113 (1993); Content et al., “Expression and preliminarydeletion analysis of the 42 kDa 2-5A synthetase induced by humaninterferon,” in Biological Interferon Systems, Proceedings of ISIR-TNOMeeting on Interferon Systems, Cantell (ed.), pages 65-72 (Nijhoff1987); Herschman, “The EGF Receptor,” in Control of Animal CellProliferation 1, Boynton et al., (eds.) pages 169-199 (Academic Press1985); Coumailleau et al., J. Biol. Chem. 270:29270 (1995); Fukunaga etal., J. Biol. Chem. 270:25291 (1995); Yamaguchi et al., Biochem.Pharmacol. 50:1295 (1995); and Meisel et al., Plant Molec. Biol. 30:1(1996).

Multiple amino acid substitutions can be made and tested using knownmethods of mutagenesis and screening, such as those disclosed byReidhaar-Olson and Sauer (Science 241:53-57, 1988) or Bowie and Sauer(Proc. Natl. Acad. Sci. USA 86:2152-2156, 1989). Briefly, these authorsdisclose methods for simultaneously randomizing two or more positions ina polypeptide, selecting for functional polypeptide, and then sequencingthe mutagenized polypeptides to determine the spectrum of allowablesubstitutions at each position. Other methods that can be used includephage display (e.g., Lowman et al., Biochem. 30:10832-10837, 1991;Ladner et al., U.S. Pat. No. 5,223,409; Huse, WIPO Publication WO92/062045) and region-directed mutagenesis (Derbyshire et al., Gene46:145, 1986; Ner et al., DNA 7:127, 1988).

Variants of the disclosed soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide DNA and polypeptide sequences can be generatedthrough DNA shuffling as disclosed by Stemmer, Nature 370:389-91, 1994,Stemmer, Proc. Natl. Acad. Sci. USA 91:10747-51, 1994 and WIPOPublication WO 97/20078. Briefly, variant DNAs are generated by in vitrohomologous recombination by random fragmentation of a parent DNAfollowed by reassembly using PCR, resulting in randomly introduced pointmutations. This technique can be modified by using a family of parentDNAs, such as allelic variants or DNAs from different species, tointroduce additional variability into the process. Selection orscreening for the desired activity, followed by additional iterations ofmutagenesis and assay provides for rapid “evolution” of sequences byselecting for desirable mutations while simultaneously selecting againstdetrimental changes.

Mutagenesis methods as disclosed herein can be combined withhigh-throughput, automated screening methods to detect zalpha11 Ligandantagonist or binding activity in host cells of cloned, mutagenizedsoluble zalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides. Preferred assays in this regard include cell proliferationassays and biosensor-based ligand-binding assays, which are describedbelow and in the Examples. Mutagenized DNA molecules that encode activereceptors or portions thereof (e.g., ligand-binding fragments, and thelike) can be recovered from the host cells and rapidly sequenced usingmodern equipment. These methods allow the rapid determination of theimportance of individual amino acid residues in a polypeptide ofinterest, and can be applied to polypeptides of unknown structure.

The present invention thus provides a series of novel, hybrid moleculesin which a segment comprising one or more of the domains of solublezalpha11 receptor is fused to another soluble receptor polypeptide.Fusion is preferably done by splicing at the DNA level to allowexpression of chimeric molecules in recombinant production systems. Theresultant molecules are then assayed for such properties as improvedsolubility, improved stability, prolonged clearance half-life, improvedexpression and secretion levels, and pharmicodynamics. Such hybridmolecules may further comprise additional amino acid residues (e.g. apolypeptide linker) between the component proteins or polypeptides.

Using the methods discussed herein, one of ordinary skill in the art canidentify and/or prepare a variety of polypeptide fragments or variantsof SEQ ID NO:6 that retain zalpha11 Ligand binding or antagonistactivity. For example, one can make a zalpha11 soluble receptor bypreparing a variety of polypeptides that are substantially homologous tothe cytokine-binding domain (residues 20 (Cys) to 237 (His) of SEQ IDNO:2 (SEQ ID NO:6), or a subsequence therein that binds zalpha11 Ligand,or allelic variants or species orthologs thereof) and retainligand-binding activity of the wild-type zalpha11 protein. Suchpolypeptides may include additional amino acids from, for example, partor all of the signal peptide sequence, transmembrane and intracellulardomains. Such polypeptides may also include additional polypeptidesegments as generally disclosed herein such as labels, affinity tags,and the like. Similarly, one of ordinary skill in the art can identifyand/or prepare a variety of polypeptide fragments or variants of SEQ IDNO:4, or other soluble class I cytokine receptors that form heterodimerswith zalpha11 receptor.

For any soluble zalpha11 receptor polypeptide, including variants, andfusion polypeptides or proteins, one of ordinary skill in the art canreadily generate a fully degenerate polynucleotide sequence encodingthat variant using the information set forth in Tables 1 and 2 above.

The soluble zalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides of the present invention, including full-length solublereceptor polypeptides, biologically active fragments, and fusionpolypeptides, can be produced in genetically engineered host cellsaccording to conventional techniques. Suitable host cells are those celltypes that can be transformed or transfected with exogenous DNA andgrown in culture, and include bacteria, fungal cells, and culturedhigher eukaryotic cells. Eukaryotic cells, particularly cultured cellsof multicellular organisms, are preferred. Techniques for manipulatingcloned DNA molecules and introducing exogenous DNA into a variety ofhost cells are disclosed by Sambrook et al., Molecular Cloning: ALaboratory Manual, 2nd ed., Cold Spring Harbor Laboratory Press, ColdSpring Harbor, N.Y., 1989, and Ausubel et al., eds., Current Protocolsin Molecular Biology, John Wiley and Sons, Inc., NY, 1987.

In general, a DNA sequence encoding a zalpha11 polypeptide is operablylinked to other genetic elements required for its expression, generallyincluding a transcription promoter and terminator, within an expressionvector. The vector will also commonly contain one or more selectablemarkers and one or more origins of replication, although those skilledin the art will recognize that within certain systems selectable markersmay be provided on separate vectors, and replication of the exogenousDNA may be provided by integration into the host cell genome. Selectionof promoters, terminators, selectable markers, vectors and otherelements is a matter of routine design within the level of ordinaryskill in the art. Many such elements are described in the literature andare available through commercial suppliers.

To direct a soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ into the secretory pathwayof a host cell, a secretory signal sequence (also known as a leadersequence, prepro sequence or pre sequence) is provided in the expressionvector. The secretory signal sequence may be that of zalpha11 receptordisclosed herein, the IL-2Rγ (amino acid 1 (Met) to 22 (Gly) of SEQ IDNO:18), or may be derived from another secreted protein (e.g., t-PA) orsynthesized de novo. The secretory signal sequence is operably linked tothe zalpha11 DNA sequence, i.e., the two sequences are joined in thecorrect reading frame and positioned to direct the newly synthesizedpolypeptide into the secretory pathway of the host cell. Secretorysignal sequences are commonly positioned 5′ to the DNA sequence encodingthe polypeptide of interest, although certain secretory signal sequencesmay be positioned elsewhere in the DNA sequence of interest (see, e.g.,Welch et al., U.S. Pat. No. 5,037,743; Holland et al., U.S. Pat. No.5,143,830).

Cultured mammalian cells are suitable hosts within the presentinvention. Methods for introducing exogenous DNA into mammalian hostcells include calcium phosphate-mediated transfection (Wigler et al.,Cell 14:725, 1978; Corsaro and Pearson, Somatic Cell Genetics 7:603,1981: Graham and Van der Eb, Virology 52:456, 1973), electroporation(Neumann et al., EMBO J. 1:841-845, 1982), DEAE-dextran mediatedtransfection (Ausubel et al., ibid.), and liposome-mediated transfection(Hawley-Nelson et al., Focus 15:73, 1993; Ciccarone et al., Focus 15:80,1993, and viral vectors (Miller and Rosman, BioTechniques 7:980-90,1989; Wang and Finer, Nature Med. 2:714-716, 1996). The production ofrecombinant polypeptides in cultured mammalian cells is disclosed, forexample, by Levinson et al., U.S. Pat. No. 4,713,339; Hagen et al., U.S.Pat. No. 4,784,950; Palmiter et al., U.S. Pat. No. 4,579,821; andRingold, U.S. Pat. No. 4,656,134. Suitable cultured mammalian cellsinclude the COS-1 (ATCC No. CRL 1650), COS-7 (ATCC No. CRL 1651), BHK(ATCC No. CRL 1632), BHK 570 (ATCC No. CRL 10314), 293 (ATCC No. CRL1573; Graham et al., J. Gen. Virol. 36:59-72, 1977) and Chinese hamsterovary (e.g. CHO-K1; ATCC No. CCL 61) cell lines. Additional suitablecell lines are known in the art and available from public depositoriessuch as the American Type Culture Collection, Rockville, Md. In general,strong transcription promoters are preferred, such as promoters fromSV-40 or cytomegalovirus (CMV). See, e.g., U.S. Pat. No. 4,956,288.Other suitable promoters include those from metallothionein genes (U.S.Pat. Nos. 4,579,821 and 4,601,978) and the adenovirus major latepromoter.

Drug selection is generally used to select for cultured mammalian cellsinto which foreign DNA has been inserted. Such cells are commonlyreferred to as “transfectants”. Cells that have been cultured in thepresence of the selective agent and are able to pass the gene ofinterest to their progeny are referred to as “stable transfectants.” Apreferred selectable marker is a gene encoding resistance to theantibiotic neomycin. Selection is carried out in the presence of aneomycin-type drug, such as G-418 or the like. Selection systems canalso be used to increase the expression level of the gene of interest, aprocess referred to as “amplification.” Amplification is carried out byculturing transfectants in the presence of a low level of the selectiveagent and then increasing the amount of selective agent to select forcells that produce high levels of the products of the introduced genes.A preferred amplifiable selectable marker is dihydrofolate reductase,which confers resistance to methotrexate. Other drug resistance genes(e.g. hygromycin resistance, multi-drug resistance, puromycinacetyltransferase) can also be used. Alternative markers that introducean altered phenotype, such as green fluorescent protein, or cell surfaceproteins such as CD4, CD8, Class I MHC, placental alkaline phosphatasemay be used to sort transfected cells from untransfected cells by suchmeans as FACS sorting, flow cytometry, or magnetic bead separationtechnology.

Other higher eukaryotic cells can also be used as hosts, including plantcells, insect cells and avian cells. The use of Agrobacterium rhizogenesas a vector for expressing genes in plant cells has been reviewed bySinkar et al., J. Biosci. (Bangalore) 11:47-58, 1987. Transformation ofinsect cells and production of foreign polypeptides therein is disclosedby Guarino et al., U.S. Pat. No. 5,162,222 and WIPO publication WO94/06463. Insect cells can be infected with recombinant baculovirus,commonly derived from Autographa californica nuclear polyhedrosis virus(AcNPV). See, King, L. A. and Possee, R. D., The Baculovirus ExpressionSystem: A Laboratory Guide, London, Chapman & Hall; O'Reilly, D. R. etal., Baculovirus Expression Vectors: A Laboratory Manual, New York,Oxford University Press., 1994; and, Richardson, C. D., Ed., BaculovirusExpression Protocols. Methods in Molecular Biology, Totowa, N.J., HumanaPress, 1995. A second method of making recombinant zalpha11 baculovirusutilizes a transposon-based system described by Luckow (Luckow, V. A, etal., J Virol 67:4566-79, 1993). This system, which utilizes transfervectors, is sold in the Bac-to-Bac™ kit (Life Technologies, Rockville,Md.). This system utilizes a transfer vector, pFastBac1™ (LifeTechnologies) containing a Tn7 transposon to move the DNA encoding thezalpha11 polypeptide into a baculovirus genome maintained in E. coli asa large plasmid called a “bacmid.” See, Hill-Perkins, M. S. and Possee,R. D., J Gen Virol 71:971-6, 1990; Bonning, B. C. et al., J Gen Virol75:1551-6, 1994; and, Chazenbalk, G. D., and Rapoport, B., J Biol Chem270:1543-9, 1995. In addition, transfer vectors can include an in-framefusion with DNA encoding an epitope tag at the C- or N-terminus of theexpressed zalpha11 polypeptide, for example, a Glu-Glu epitope tag(Grussenmeyer, T. et al., Proc. Natl. Acad. Sci. 82:7952-4, 1985). Usinga technique known in the art, a transfer vector containing zalpha11 istransformed into E. Coli, and screened for bacmids which contain aninterrupted lacZ gene indicative of recombinant baculovirus. The bacmidDNA containing the recombinant baculovirus genome is isolated, usingcommon techniques, and used to transfect Spodoptera frugiperda cells,e.g. Sf9 cells. Recombinant virus that expresses zalpha11 issubsequently produced. Recombinant viral stocks are made by methodscommonly used in the art.

The recombinant virus is used to infect host cells, typically a cellline derived from the fall armyworm, Spodoptera frugiperda. See, ingeneral, Glick and Pasternak, Molecular Biotechnology: Principles andApplications of Recombinant DNA, ASM Press, Washington, D.C., 1994.Another suitable cell line is the High FiveO™ cell line (Invitrogen)derived from Trichoplusia ni (U.S. Pat. No. 5,300,435). Commerciallyavailable serum-free media are used to grow and maintain the cells.Suitable media are Sf900 II™ (Life Technologies) or ESF 921™ (ExpressionSystems) for the Sf9 cells; and Ex-cellO405™ (JRH Biosciences, Lenexa,Kans.) or Express FiveO™ (Life Technologies) for the T. ni cells.Procedures used are generally described in available laboratory manuals(King, L. A. and Possee, R. D., ibid.; O'Reilly, D. R. et al., ibid.;Richardson, C. D., ibid.). Subsequent purification of the zalpha11polypeptide from the supernatant can be achieved using methods describedherein.

Fungal cells, including yeast cells, can also be used within the presentinvention. Yeast species of particular interest in this regard includeSaccharomyces cerevisiae, Pichia pastoris, and Pichia methanolica.Methods for transforming S. cerevisiae cells with exogenous DNA andproducing recombinant polypeptides therefrom are disclosed by, forexample, Kawasaki, U.S. Pat. No. 4,599,311; Kawasaki et al., U.S. Pat.No. 4,931,373; Brake, U.S. Pat. No. 4,870,008; Welch et al., U.S. Pat.No. 5,037,743; and Murray et al., U.S. Pat. No. 4,845,075. Transformedcells are selected by phenotype determined by the selectable marker,commonly drug resistance or the ability to grow in the absence of aparticular nutrient (e.g., leucine). A preferred vector system for usein Saccharomyces cerevisiae is the POT1 vector system disclosed byKawasaki et al. (U.S. Pat. No. 4,931,373), which allows transformedcells to be selected by growth in glucose-containing media. Suitablepromoters and terminators for use in yeast include those from glycolyticenzyme genes (see, e.g., Kawasaki, U.S. Pat. No. 4,599,311; Kingsman etal., U.S. Pat. No. 4,615,974; and Bitter, U.S. Pat. No. 4,977,092) andalcohol dehydrogenase genes. See also U.S. Pat. Nos. 4,990,446;5,063,154; 5,139,936 and 4,661,454. Transformation systems for otheryeasts, including Hansenula polymorpha, Schizosaccharomyces pombe,Kluyveromyces lactis, Kluyveromyces fragilis, Ustilago maydis, Pichiapastoris, Pichia methanolica, Pichia guillermondii and Candida maltosaare known in the art. See, for example, Gleeson et al., J. Gen.Microbiol. 132:3459-3465, 1986 and Cregg, U.S. Pat. No. 4,882,279.Aspergillus cells may be utilized according to the methods of McKnightet al., U.S. Pat. No. 4,935,349. Methods for transforming Acremoniumchrysogenum are disclosed by Sumino et al., U.S. Pat. No. 5,162,228.Methods for transforming Neurospora are disclosed by Lambowitz, U.S.Pat. No. 4,486,533.

The use of Pichia methanolica as host for the production of recombinantproteins is disclosed in WIPO Publications WO 97/17450, WO 97/17451, WO98/02536, and WO 98/02565. DNA molecules for use in transforming P.methanolica will commonly be prepared as double-stranded, circularplasmids, which are preferably linearized prior to transformation. Forpolypeptide production in P. methanolica, it is preferred that thepromoter and terminator in the plasmid be that of a P. methanolica gene,such as a P. methanolica alcohol utilization gene (AUG1 or AUG2). Otheruseful promoters include those of the dihydroxyacetone synthase (DHAS),formate dehydrogenase (FMD), and catalase (CAT) genes. To facilitateintegration of the DNA into the host chromosome, it is preferred to havethe entire expression segment of the plasmid flanked at both ends byhost DNA sequences. A preferred selectable marker for use in Pichiamethanolica is a P. methanolica ADE2 gene, which encodesphosphoribosyl-5-aminoimidazole carboxylase (AIRC; EC 4.1.1.21), whichallows ade2 host cells to grow in the absence of adenine. Forlarge-scale, industrial processes where it is desirable to minimize theuse of methanol, it is preferred to use host cells in which bothmethanol utilization genes (AUG1 and AUG2) are deleted. For productionof secreted proteins, host cells deficient in vacuolar protease genes(PEP4 and PRB1) are preferred. Electroporation is used to facilitate theintroduction of a plasmid containing DNA encoding a polypeptide ofinterest into P. methanolica cells. It is preferred to transform P.methanolica cells by electroporation using an exponentially decaying,pulsed electric field having a field strength of from 2.5 to 4.5 kV/cm,preferably about 3.75 kV/cm, and a time constant (t) of from 1 to 40milliseconds, most preferably about 20 milliseconds.

Prokaryotic host cells, including strains of the bacteria Escherichiacoli, Bacillus and other genera are also useful host cells within thepresent invention. Techniques for transforming these hosts andexpressing foreign DNA sequences cloned therein are well known in theart (see, e.g., Sambrook et al., ibid.). When expressing a zalpha11polypeptide in bacteria such as E. coli, the polypeptide may be retainedin the cytoplasm, typically as insoluble granules, or may be directed tothe periplasmic space by a bacterial secretion sequence. In the formercase, the cells are lysed, and the granules are recovered and denaturedusing, for example, guanidine isothiocyanate or urea. The denaturedpolypeptide can then be refolded and dimerized by diluting thedenaturant, such as by dialysis against a solution of urea and acombination of reduced and oxidized glutathione, followed by dialysisagainst a buffered saline solution. In the latter case, the polypeptidecan be recovered from the periplasmic space in a soluble and functionalform by disrupting the cells (by, for example, sonication or osmoticshock) to release the contents of the periplasmic space and recoveringthe protein, thereby obviating the need for denaturation and refolding.

Transformed or transfected host cells are cultured according toconventional procedures in a culture medium containing nutrients andother components required for the growth of the chosen host cells. Avariety of suitable media, including defined media and complex media,are known in the art and generally include a carbon source, a nitrogensource, essential amino acids, vitamins and minerals. Media may alsocontain such components as growth factors or serum, as required. Thegrowth medium will generally select for cells containing the exogenouslyadded DNA by, for example, drug selection or deficiency in an essentialnutrient which is complemented by the selectable marker carried on theexpression vector or co-transfected into the host cell. P. methanolicacells are cultured in a medium comprising adequate sources of carbon,nitrogen and trace nutrients at a temperature of about 25° C. to 35° C.Liquid cultures are provided with sufficient aeration by conventionalmeans, such as shaking of small flasks or sparging of fermentors. Apreferred culture medium for P. methanolica is YEPD (2% D-glucose, 2%Bacto™ Peptone (Difco Laboratories, Detroit, Mich.), 1% Bacto™ yeastextract (Difco Laboratories), 0.004% adenine and 0.006% L-leucine).

Mammalian cells suitable for use in assaying antagonist activity of thenovel soluble receptors of the present invention express a zalpha11receptor or receptor fusion capable of signaling and transducing areceptor-mediated signal of the zalpha11 Ligand. Such cells includecells that express a β-subunit, such as gp130, IL-2Rγ and cells thatco-express receptors (Gearing et al., EMBO J. 10:2839-2848, 1991;Gearing et al., U.S. Pat. No. 5,284,755). In this regard it is generallypreferred to employ a cell that is responsive to other cytokines thatbind to receptors in the same subfamily, such as IL-6 or LIF, becausesuch cells will contain the requisite signal transduction pathway(s).Preferred cells of this type include the human TF-1 cell line (ATCCnumber CRL-2003) and the DA-1 cell line (Branch et al., Blood 69:1782,1987; Broudy et al., Blood 75:1622-1626, 1990). In the alternative,suitable host cells can be engineered to produce a β-subunit or othercellular component needed for the desired cellular response. Forexample, the murine cell line BaF3 (Palacios and Steinmetz, Cell41:727-734, 1985; Mathey-Prevot et al., Mol. Cell. Biol. 6: 4133-4135,1986) has been used to produce a cell line responsive to the zalpha11Ligand (see Examples). Other such lines include a baby hamster kidney(BHK) cell line, or the CTLL-2 cell line (ATCC TIB-214) can betransfected to express an IL-2Rγ subunit in addition to zalpha11receptor. It is generally preferred to use a host cell and receptor(s)from the same species, however this approach allows cell lines to beengineered to express multiple receptor subunits from any species,thereby overcoming potential limitations arising from speciesspecificity. In the alternative, species homologs of the human receptorcDNA can be cloned and used within cell lines from the same species,such as a mouse cDNA in the BaF3 cell line. Cell lines that aredependent upon one hematopoietic growth factor, such as IL-3, can thusbe engineered to become dependent upon a zalpha11 ligand. Such cells canbe used as described herein in the presence of zalpha11 Ligand to assessthe antagonist activity of soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ on zalpha11Ligand signaling and proliferative activity.

Cells expressing functional soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ areused within screening assays. A variety of suitable assays are known inthe art. These assays are based on the detection of a biologicalresponse in the target cell to the zalpha11 Ligand in the presence orabsence of the soluble receptors of the present invention. One suchassay is a cell proliferation assay. Cells are cultured in the presenceor absence of zalpha11 Ligand with or without the addition othercytokines or proliferative agents, and cell proliferation is detectedby, for example, measuring incorporation of tritiated thymidine or bycolorimetric assay based on the metabolic breakdown of Alamar Blue™(AccuMed, Chicago, Ill.) or 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) (Mosman, J. Immunol. Meth. 65: 55-63, 1983).An alternative assay format uses cells that are further engineered toexpress a reporter gene. The reporter gene is linked to a promoterelement that is responsive to the receptor-linked pathway, and the assaydetects activation of transcription of the reporter gene. DNA responseelements can include, but are not limited to, cyclic AMP responseelements (CRE), hormone response elements (HRE) insulin response element(IRE) (Nasrin et al., Proc. Natl. Acad. Sci. USA 87:5273-7, 1990) andserum response elements (SRE) (Shaw et al. Cell 56: 563-72, 1989).Cyclic AMP response elements are reviewed in Roestler et al., J. Biol.Chem. 263 (19):9063-6; 1988 and Habener, Molec. Endocrinol. 4(8):1087-94; 1990. Hormone response elements are reviewed in Beato, Cell56:335-44; 1989. A preferred promoter element in this regard is a serumresponse element, or SRE (see, for example, Shaw et al., Cell56:563-572, 1989). A preferred such reporter gene is a luciferase gene(de Wet et al., Mol. Cell. Biol. 7:725, 1987). Expression of theluciferase gene is detected by luminescence using methods known in theart (e.g., Baumgartner et al., J. Biol. Chem. 269:19094-29101, 1994;Schenborn and Goiffin, Promega Notes 41:11, 1993). Luciferase assay kitsare commercially available from, for example, Promega Corp., Madison,Wis. Target cell lines of this type can be used to screen libraries ofchemicals, cell-conditioned culture media, fungal broths, soil samples,water samples, and the like for antagonist activity. Such cells can beused as described herein in the presence of zalpha11 Ligand in acompetitive inhibition type assay to assess the antagonist activity ofsoluble zalpha11 receptor or soluble zalpha11 heterodimeric polypeptide,such as soluble zalpha11/IL-2Rγ on zalpha11 Ligand signaling andproliferative activity.

T- and B-cell proliferation assay methods can also be used to assess theantagonist activity of soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ on zalpha11Ligand signaling and proliferative activity in the presence of othercytokines, for example, IL-15, Flt3 and the like. Such assays aredescribed in the examples herein, and are know in the art. Briefly,using flow cytometry, mature or immature subsets of T-cells or B-cellsare isolated based on the presence or absence of various cell surfacemolecules (e.g., CD4, CD8, CD19, CD3, CD40, CD28, etc.). Cells can beselected prior to or after exposure to zalpha11 Ligand, depending on thecell type being studied, and the effect of zalpha11 Ligand thereon. Thesoluble receptors or antibodies of the present invention can be added ata range of concentrations to assess the antagonistic or binding activityon the Ligand in the T-cell or B-cell proliferation assay. Such assaysare well known in the art, and described herein.

Moreover, a secretion trap method employing soluble zalpha11 receptor orsoluble zalpha11 heterodimeric receptor polypeptides can be used toisolate transfected cells that express zalpha11 Ligand. For the method,see, Aldrich, et al, Cell 87: 1161-1169, 1996. A cDNA expression libraryprepared from a known or suspected ligand source is transfected intoCOS-7 cells. The cDNA library vector generally has an SV40 origin foramplification in COS-7 cells, and a CMV promoter for high expression.The transfected COS-7 cells are grown in a monolayer and then fixed andpermeabilized. Tagged or biotin-labeled soluble zalpha11 receptor orsoluble zalpha11 heterodimeric receptor polypeptides, described herein,is then placed in contact with the cell layer and allowed to bind cellsin the monolayer that express an anti-complementary molecule, i.e., azalpha11 Ligand. A cell expressing a ligand will thus be bound withreceptor molecules. An anti-tag antibody (anti-Ig for Ig fusions, M2 oranti-FLAG for FLAG-tagged fusions, streptavidin, and the like) which isconjugated with horseradish peroxidase (HRP) is used to visualize thesecells to which the tagged or biotin-labeled soluble zalpha11 receptor orsoluble zalpha11 heterodimeric receptor polypeptides has bound. The HRPcatalyzes deposition of a tyramide reagent, for example, tyramide-FITC.A commercially-available kit can be used for this detection (forexample, Renaissance TSA-Direct™ Kit; NEN Life Science Products, Boston,Mass.). Cells which express zalpha11 receptor Ligand will be identifiedunder fluorescence microscopy as green cells and picked for subsequentcloning of the ligand using procedures for plasmid rescue as outlined inAldrich, et al, supra., followed by subsequent rounds of secretion trapassay until single clones are identified.

Moreover, histologic and immunohistochemical methods employing solublezalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides can be used to identify cells and tissues cells thatexpress zalpha11 Ligand. Such methods are known in the art and describedherein.

Additional assays to detect the antagonist or binding activity ofsoluble zalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides provided by the present invention include the use of hybridreceptor polypeptides. These hybrid polypeptides fall into two generalclasses. Within the first class, the intracellular domain of zalpha11,comprising approximately residues 256 (Lys) to 528 (Ser) of SEQ ID NO:2,is joined to the ligand-binding domain of a second receptor. It ispreferred that the second receptor be a hematopoietic cytokine receptor,such as mpl receptor (Souyri et al., Cell 63:1137-1147, 1990). Thehybrid receptor will further comprise a transmembrane domain, which maybe derived from either receptor. A DNA construct encoding the hybridreceptor is then inserted into a host cell. Cells expressing the hybridreceptor are cultured in the presence of a ligand for the binding domainand assayed for a response. This system provides a means for analyzingsignal transduction mediated by zalpha11 while using readily availableligands. This system can also be used to determine if particular celllines are capable of responding to signals transduced by zalpha11. Asecond class of hybrid receptor polypeptides comprise the extracellular(ligand-binding) domain of zalpha11 (approximately residues 20 (Cys) to237 (His) of SEQ ID NO:2) (SEQ ID NO:6) with a cytoplasmic domain of asecond receptor, preferably a cytokine receptor, and a transmembranedomain. The transmembrane domain may be derived from either receptor.Such hybrid receptors are expressed in cells known to be capable ofresponding to signals transduced by the receptor comprising theextracellular domain, such as in the presence of the zalpha11 Ligand.Addition of the soluble zalpha11 receptor or soluble zalpha11heterodimeric receptor polypeptides, in the presence of the zalpha11Ligand, is used to assess the zalpha11 Ligand antagonist or bindingactivity of the soluble zalpha11 receptor or soluble zalpha11heterodimeric receptor polypeptides to the zalpha11 Ligand.

The tissue specificity and biological activities of zalpha11 Ligandexpression suggest a role in early NK cell and thymocyte development,mature B-cell expansion, general immune response stimulation, and immuneresponse regulation. These processes involve stimulation of cellproliferation and differentiation in response to the binding of thezalpha11 Ligand to its cognate receptor, comprising at least onezalpha11 receptor subunit. In view of the biological activity observedfor this Ligand, antagonists have enormous potential in both in vitroand in vivo applications. As antagonists of the zalpha11 Ligand, solublezalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides can find utility in the suppression of the immune system,such as in the treatment of autoimmune diseases, including rheumatoidarthritis, multiple sclerosis, diabetes mellitus, inflammatory boweldisease, Crohn's disease, and the like. Immune suppression can also beused to reduce rejection of tissue or organ transplants and grafts andto treat B-cell malignancies, T-cell specific leukemias or lymphomas byinhibiting proliferation of the affected cell type.

Soluble zalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides may also be used within diagnostic systems for thedetection of circulating levels of zalpha11 Ligand. Within a relatedembodiment, antibodies or other agents that specifically bind to solublezalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides can be used to detect circulating receptor polypeptides.Elevated or depressed levels of Ligand or receptor polypeptides may beindicative of pathological conditions, including cancer. Solublereceptor polypeptides may contribute to pathologic processes and can bean indirect marker of an underlying disease. For example, elevatedlevels of soluble IL-2 receptor in human serum have been associated witha wide variety of inflammatory and neoplastic conditions, such asmyocardial infarction, asthma, myasthenia gravis, rheumatoid arthritis,acute T-cell leukemia, B-cell lymphomas, chronic lymphocytic leukemia,colon cancer, breast cancer, and ovarian cancer (Heaney et al., Blood87:847-857, 1996).

A ligand-binding polypeptide of a zalpha11 receptor, such as solublezalpha11 receptor or soluble zalpha11 heterodimeric polypeptide, such assoluble zalpha11/IL-2Rγ can be prepared by expressing a truncated DNAencoding the zalpha11 cytokine binding domain (approximately residue 20(Cys) through residue 237 (His) of the human receptor (SEQ ID NO:2) (SEQID NO:6)) or the corresponding region of a non-human receptor (e.g., SEQID NO:12). A soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ can be prepared by co-expressing a truncated DNAencoding the zalpha11 cytokine binding domain (SEQ ID NO:6) and thetruncated DNA encoding the extracellular domain of another class Icytokine receptor, such as IL-2Rγ (SEQ ID NO:4). It is preferred thatthe extracellular domains of the soluble zalpha11 homodimer orheterodimer be prepared in a form substantially free of transmembraneand intracellular polypeptide segments. Moreover, ligand-bindingpolypeptide fragments within the soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide (e.g., soluble zalpha11/IL-2Rγ), orcytokine-binding domain, described above, can also serve as zalpha11soluble receptors for uses described herein. To direct the export of areceptor polypeptide from the host cell, the receptor DNA is linked to asecond DNA segment encoding a secretory peptide, such as a t-PAsecretory peptide, secretory peptide from another cytokine receptor,other secreted molecule, or a zalpha11 receptor secretory peptide. Tofacilitate purification of the secreted receptor polypeptide, aC-terminal extension, such as a poly-histidine tag, substance P, Flag™peptide (Hopp et al., Bio/Technology 6:1204-1210, 1988; available fromEastman Kodak Co., New Haven, Conn.), Glu-glu tag (SEQ ID NO:14) oranother polypeptide or protein for which an antibody or other specificbinding agent is available, can be fused to the soluble receptorpolypeptide.

In an alternative approach, a receptor extracellular domain can beexpressed as a fusion with immunoglobulin heavy chain constant regions,typically an F_(C) fragment, which contains two constant region domainsand lacks the variable region. Such fusions are typically secreted asmultimeric molecules wherein the Fc portions are disulfide bonded toeach other and two receptor polypeptides are arrayed in close proximityto each other. Fusions of this type can be used to affinity purify thecognate ligand from solution, as an in vitro assay tool, to blocksignals in vitro by specifically titrating out Ligand, and asantagonists in vivo by administering them parenterally to bindcirculating ligand and clear it from the circulation. To purify ligand,a zalpha11-Ig chimera (e.g., Zalpha11-Fc4 described herein), is added toa sample containing the ligand (e.g., cell-conditioned culture media ortissue extracts) under conditions that facilitate receptor-ligandbinding (typically near-physiological temperature, pH, and ionicstrength). The chimera-ligand complex is then separated by the mixtureusing protein A, immobilized on a solid support (e.g., insoluble resinbeads). The ligand is then eluted using conventional chemicaltechniques, such as with a salt or pH gradient. In the alternative, thechimera itself can be bound to a solid support, with binding and elutioncarried out as above. Collected fractions can be re-fractionated untilthe desired level of purity is reached.

Moreover, soluble zalpha11 receptor or soluble zalpha11 heterodimericreceptor polypeptides, such as soluble zalpha11/IL-2Rγ, can be used as a“ligand sink,” i.e., antagonist, to bind ligand in vivo or in vitro intherapeutic or other applications where the presence of the ligand isnot desired. For example, in cancers that are expressing large amountsof bioactive zalpha11 Ligand, soluble zalpha11 receptor or solublezalpha11 heterodimeric receptor polypeptides, such as solublezalpha11/IL-2Rγ can be used as a direct antagonist of the ligand invivo, and may aid in reducing progression and symptoms associated withthe disease, and can be used in conjunction with other therapies (e.g.,chemotherapy) to enhance the effect of the therapy in reducingprogression and symptoms, and preventing relapse. Moreover, solublezalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides, such as soluble zalpha11/IL-2Rγ can be used to slow theprogression of cancers that over-express zalpha11 receptors, by bindingligand in vivo that would otherwise enhance proliferation of thosecancers.

Moreover, soluble zalpha11 receptor or soluble zalpha11 heterodimericreceptor polypeptides, such as soluble zalpha11/IL-2Rγ can be used invivo or in diagnostic applications to detect zalpha11 Ligand-expressingcancers in vivo or in tissue samples. For example, the soluble zalpha11receptor or soluble zalpha11 heterodimeric receptor polypeptides, suchas soluble zalpha11/IL-2Rγ can be conjugated to a radio-label orfluorescent label as described herein, and used to detect the presenceof the zalpha11 Ligand in a tissue sample using an in vitroligand-receptor type binding assay, or fluorescent imaging assay.Moreover, a radiolabeled soluble zalpha11 receptor or soluble zalpha11heterodimeric receptor polypeptides, such as soluble zalpha11/IL-2Rγcould be administered in vivo to detect Ligand-expressing solid tumorsthrough a radio-imaging method known in the art.

It is preferred to purify the polypeptides of the present invention to≧80% purity, more preferably to ≧90% purity, even more preferably ≧95%purity, and particularly preferred is a pharmaceutically pure state,that is greater than 99.9% pure with respect to contaminatingmacromolecules, particularly other proteins and nucleic acids, and freeof infectious and pyrogenic agents. Preferably, a purified polypeptideis substantially free of other polypeptides, particularly otherpolypeptides of animal origin.

Expressed recombinant soluble zalpha11 receptor or soluble zalpha11heterodimeric receptor polypeptides, such as soluble zalpha11/IL-2Rγ (orzalpha11 chimeric or fusion polypeptides) can be purified usingfractionation and/or conventional purification methods and media.Ammonium sulfate precipitation and acid or chaotrope extraction may beused for fractionation of samples. Exemplary purification steps mayinclude hydroxyapatite, size exclusion, FPLC and reverse-phase highperformance liquid chromatography. Suitable chromatographic mediainclude derivatized dextrans, agarose, cellulose, polyacrylamide,specialty silicas, and the like. PEI, DEAE, QAE and Q derivatives arepreferred. Exemplary chromatographic media include those mediaderivatized with phenyl, butyl, or octyl groups, such asPhenyl-Sepharose FF (Pharmacia), Toyopearl butyl 650 (Toso Haas,Montgomeryville, Pa.), Octyl-Sepharose (Pharmacia) and the like; orpolyacrylic resins, such as Amberchrom CG 71 (Toso Haas) and the like.Suitable solid supports include glass beads, silica-based resins,cellulosic resins, agarose beads, cross-linked agarose beads,polystyrene beads, cross-linked polyacrylamide resins and the like thatare insoluble under the conditions in which they are to be used. Thesesupports may be modified with reactive groups that allow attachment ofproteins by amino groups, carboxyl groups, sulfhydryl groups, hydroxylgroups and/or carbohydrate moieties. Examples of coupling chemistriesinclude cyanogen bromide activation, N-hydroxysuccinimide activation,epoxide activation, sulfhydryl activation, hydrazide activation, andcarboxyl and amino derivatives for carbodiimide coupling chemistries.These and other solid media are well known and widely used in the art,and are available from commercial suppliers. Methods for bindingreceptor polypeptides to support media are well known in the art.Selection of a particular method is a matter of routine design and isdetermined in part by the properties of the chosen support. See, forexample, Affinity Chromatography: Principles & Methods, Pharmacia LKBBiotechnology, Uppsala, Sweden, 1988.

The polypeptides of the present invention can be isolated byexploitation of their biochemical, structural, and biologicalproperties. For example, immobilized metal ion adsorption (IMAC)chromatography can be used to purify histidine-rich proteins, includingthose comprising polyhistidine tags. Briefly, a gel is first chargedwith divalent metal ions to form a chelate (Sulkowski, Trends inBiochem. 3:1-7, 1985). Histidine-rich proteins will be adsorbed to thismatrix with differing affinities, depending upon the metal ion used, andwill be eluted by competitive elution, lowering the pH, or use of strongchelating agents. Other methods of purification include purification ofglycosylated proteins by lectin affinity chromatography and ion exchangechromatography (Methods in Enzymol., Vol. 182, “Guide to ProteinPurification”, M. Deutscher, (ed.), Acad. Press, San Diego, 1990, pp.529-39). Within additional embodiments of the invention, a fusion of thepolypeptide of interest and an affinity tag (e.g., maltose-bindingprotein, an immunoglobulin domain) may be constructed to facilitatepurification. Moreover zalpha11 Ligand affinity columns can be used topurify soluble zalpha11 receptor or soluble zalpha11 heterodimericreceptor polypeptides, such as soluble zalpha11/IL-2Rγ. Such affinitychromatography methods are well known in the art.

Moreover, using methods described in the art, polypeptide fusions, orhybrid zalpha11 proteins, are constructed using regions or domains ofthe inventive zalpha11 in combination with those of other human cytokinereceptor family proteins, or heterologous proteins (Sambrook et al.,ibid., Altschul et al., ibid., Picard, Cur. Opin. Biology, 5:511-5,1994, and references therein). These methods allow the determination ofthe biological importance of larger domains or regions in a polypeptideof interest. Such hybrids may alter reaction kinetics, binding,constrict or expand the substrate specificity, or alter tissue andcellular localization of a polypeptide, and can be applied topolypeptides of unknown structure.

Soluble receptor fusion polypeptides or proteins can be prepared bymethods known to those skilled in the art by preparing each component ofthe fusion protein and chemically conjugating them. Alternatively, apolynucleotide encoding one or more components of the fusion protein inthe proper reading frame can be generated using known techniques andexpressed by the methods described herein. For example, part or all of adomain(s) conferring a biological function may be swapped betweenzalpha11 of the present invention with the functionally equivalentdomain(s) from another cytokine family member. Such domains include, butare not limited to, the extracellular cytokine binding domain, ligandbinding domain and residues, transmembrane domain, as disclosed herein.Such fusion proteins would be expected to have a biological functionalprofile that is the same or similar to polypeptides of the presentinvention or other known family proteins, depending on the fusionconstructed. Moreover, such fusion proteins may exhibit other propertiesas disclosed herein.

Standard molecular biological and cloning techniques can be used to swapthe equivalent domains between the zalpha11 polypeptide and thosepolypeptides to which they are fused. Generally, a DNA segment thatencodes a domain of interest, e.g., a zalpha11 domain described herein,is operably linked in frame to at least one other DNA segment encodingan additional polypeptide (for instance a domain or region from anothercytokine receptor, such as the IL-2Rγ receptor), and inserted into anappropriate expression vector, as described herein. Generally DNAconstructs are made such that the several DNA segments that encode thecorresponding regions of a polypeptide are operably linked in frame tomake a single construct that encodes the entire fusion protein, or afunctional portion thereof. For example, a DNA construct would encodefrom N-terminus to C-terminus a fusion protein comprising a signalpolypeptide followed by a cytokine-binding domain. Such fusion proteinscan be expressed, isolated, and assayed for activity as describedherein.

Soluble zalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides, such as soluble zalpha11/IL-2Rγ polypeptides, or fragmentsthereof may also be prepared through chemical synthesis. Suchpolypeptides may be monomers or multimers; glycosylated ornon-glycosylated; pegylated or non-pegylated; and may or may not includean initial methionine amino acid residue.

Polypeptides of the present invention can also be synthesized byexclusive solid phase synthesis, partial solid phase methods, fragmentcondensation or classical solution synthesis. Methods for synthesizingpolypeptides are well known in the art. See, for example, Merrifield, J.Am. Chem. Soc. 85:2149, 1963; and Kaiser et al., Anal. Biochem. 34:595,1970. After the entire synthesis of the desired peptide on a solidsupport, the peptide-resin is with a reagent that cleaves thepolypeptide from the resin and removes most of the side-chain protectinggroups. Such methods are well established in the art.

The activity of molecules of the present invention can be measured usinga variety of assays that measure cell differentiation and proliferation.Such assays are well known in the art and described herein.

Proteins of the present invention are useful for example, in treatinglymphoid, immune, hematopoietic, inflammatory disorders and the like,and can be measured in vitro using cultured cells or in vivo byadministering molecules of the claimed invention to the appropriateanimal model. For instance, host cells expressing a soluble zalpha11receptor or soluble zalpha11 heterodimeric receptor polypeptides, suchas soluble zalpha11/IL-2Rγ can be embedded in an alginate environmentand injected (implanted) into recipient animals. Alginate-poly-L-lysinemicroencapsulation, permselective membrane encapsulation and diffusionchambers are a means to entrap transfected mammalian cells or primarymammalian cells. These types of non-immunogenic “encapsulations” permitthe diffusion of proteins and other macromolecules secreted or releasedby the captured cells to the recipient animal. Most importantly, thecapsules mask and shield the foreign, embedded cells from the recipientanimal's immune response. Such encapsulations can extend the life of theinjected cells from a few hours or days (naked cells) to several weeks(embedded cells). Alginate threads provide a simple and quick means forgenerating embedded cells.

The materials needed to generate the alginate threads are known in theart. In an exemplary procedure, 3% alginate is prepared in sterile H₂O,and sterile filtered. Just prior to preparation of alginate threads, thealginate solution is again filtered. An approximately 50% cellsuspension (containing about 5×10⁵ to about 5×10⁷ cells/ml) is mixedwith the 3% alginate solution. One ml of the alginate/cell suspension isextruded into a 100 mM sterile filtered CaCl₂ solution over a timeperiod of ˜15 min, forming a “thread”. The extruded thread is thentransferred into a solution of 50 mM CaCl₂, and then into a solution of25 mM CaCl₂. The thread is then rinsed with deionized water beforecoating the thread by incubating in a 0.01% solution of poly-L-lysine.Finally, the thread is rinsed with Lactated Ringer's Solution and drawnfrom solution into a syringe barrel (without needle). A large boreneedle is then attached to the syringe, and the thread isintraperitoneally injected into a recipient in a minimal volume of theLactated Ringer's Solution.

Adenoviral and other viral systems, such as vaccinia virus can be usedto express and produce the proteins of the present invention. Forexample, using adenovirus vectors where portions of the adenovirusgenome are deleted, inserts are incorporated into the viral DNA bydirect ligation or by homologous recombination with a co-transfectedplasmid. In an exemplary system, the essential E1 gene has been deletedfrom the viral vector, and the virus will not replicate unless the E1gene is provided by the host cell (the human 293 cell line isexemplary). If the adenoviral delivery system has an E1 gene deletion,the virus cannot replicate in human cells, but will express and process(and, if a secretory signal sequence is present, secrete) theheterologous protein. Moreover, by deleting the entire adenovirusgenome, very large inserts of heterologous DNA can be accommodated.Generation of so called “gutless” adenoviruses where all viral genes aredeleted are particularly advantageous for insertion of large inserts ofheterologous DNA. For review, see Yeh, P. and Perricaudet, M., FASEB J.11:615-623, 1997.

The adenovirus system can be used for protein production in vitro. Byculturing adenovirus-infected non-293 cells under conditions where thecells are not rapidly dividing, the cells can produce proteins forextended periods of time. For instance, BHK cells are grown toconfluence in cell factories, are exposed to the adenoviral vectorencoding the secreted protein of interest. The cells are then grownunder serum-free conditions, which allows infected cells to survive forseveral weeks without significant cell division. Alternatively,adenovirus vector infected 293 cells can be grown as adherent cells orin suspension culture at relatively high cell density to producesignificant amounts of protein (See Garnier et al., Cytotechnol.15:145-55, 1994). With either protocol, an expressed, secretedheterologous protein can be repeatedly isolated from the cell culturesupernatant, lysate, or membrane fractions depending on the dispositionof the expressed protein in the cell. Within the infected 293 cellproduction protocol, non-secreted proteins may also be effectivelyobtained.

Soluble zalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides, such as soluble zalpha11/IL-2Rγ receptor antagonists canbe used in vitro in an assay to measure a decrease in stimulation ofcolony formation by zalpha11 Ligand from isolated primary bone marrowcultures. Such assays are disclosed herein and are well known in theart.

Zalpha11 Ligand antagonists and binding agents are also useful asresearch reagents for characterizing sites of ligand-receptorinteraction. Inhibitors of zalpha11 Ligand activity (zalpha11 Ligandantagonists) include anti-soluble zalpha11 receptor or anti-solublezalpha11 heterodimeric receptor polypeptide antibodues, such asanti-soluble zalpha11/IL-2Rγ antibodies and soluble zalpha11 receptor orsoluble zalpha11 heterodimeric receptor polypeptides, such as solublezalpha11/IL-2Rγ receptors, as well as other peptidic and non-peptidicagents (including ribozymes).

A soluble zalpha11 receptor or soluble zalpha11 heterodimeric receptorpolypeptides, such as soluble zalpha11/IL-2Rγ ligand-binding polypeptideof the present invention, can also be used for purification of zalpha11Ligand. The polypeptide is immobilized on a solid support, such as beadsof agarose, cross-linked agarose, glass, cellulosic resins, silica-basedresins, polystyrene, cross-linked polyacrylamide, or like materials thatare stable under the conditions of use. Methods for linking polypeptidesto solid supports are known in the art, and include amine chemistry,cyanogen bromide activation, N-hydroxysuccinimide activation, epoxideactivation, sulfhydryl activation, and hydrazide activation. Theresulting medium will generally be configured in the form of a column,and fluids containing ligand are passed through the column one or moretimes to allow ligand to bind to the receptor polypeptide. The ligand isthen eluted using changes in salt concentration, chaotropic agents(guanidine HCl), or pH to disrupt ligand-receptor binding.

An assay system that uses a ligand-binding receptor (or an antibody, onemember of a complement/anti-complement pair) or a binding fragmentthereof, and a commercially available biosensor instrument may beadvantageously employed (e.g., BIAcore™, Pharmacia Biosensor,Piscataway, N.J.; or SELDI™ technology, Ciphergen, Inc., Palo Alto,Calif.). Such receptor, antibody, member of a complement/anti-complementpair or fragment is immobilized onto the surface of a receptor chip. Useof this instrument is disclosed by Karlsson, J. Immunol. Methods145:229-240, 1991 and Cunningham and Wells, J. Mol. Biol. 234:554-63,1993. A receptor, antibody, member or fragment is covalently attached,using amine or sulfhydryl chemistry, to dextran fibers that are attachedto gold film within the flow cell. A test sample is passed through thecell. If a ligand, epitope, or opposite member of thecomplement/anti-complement pair is present in the sample, it will bindto the immobilized receptor, antibody or member, respectively, causing achange in the refractive index of the medium, which is detected as achange in surface plasmon resonance of the gold film. This system allowsthe determination of on- and off-rates, from which binding affinity canbe calculated, and assessment of stoichiometry of binding.

Ligand-binding receptor polypeptides, such as those of the presentinvention, can also be used within other assay systems known in the art.Such systems include Scatchard analysis for determination of bindingaffinity (see Scatchard, Ann. NY Acad. Sci. 51: 660-672, 1949) andcalorimetric assays (Cunningham et al., Science 253:545-48, 1991;Cunningham et al., Science 245:821-25, 1991).

Soluble zalpha11 receptor or soluble zalpha11 heterodimeric polypeptide,such as soluble zalpha11/IL-2Rγ polypeptides can also be used to prepareantibodies that bind to epitopes, peptides, or polypeptides containedwithin the antigen. The zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ polypeptidesor a fragment thereof serves as an antigen (immunogen) to inoculate ananimal and elicit an immune response. One of skill in the art wouldrecognize that antigenic, epitope-bearing polypeptides contain asequence of at least 6, preferably at least 9, and more preferably atleast 15 to about 30 contiguous amino acid residues of a zalpha11receptor or soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ polypeptides (e.g., SEQ ID NO:2, SEQ ID NO:6, SEQ IDNO:4). Polypeptides comprising a larger portion of a zalpha11 receptoror soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ polypeptides i.e., from 30 to 100 residues up to theentire length of the amino acid sequence are included. Antigens orimmunogenic epitopes can also include attached tags, adjuvants andcarriers, as described herein. Suitable antigens include the zalpha11polypeptide encoded by SEQ ID NO:2 from amino acid number 20 (Cys) toamino acid number 237 (His) (SEQ ID NO:6), or a contiguous 9 to 218 AAamino acid fragment thereof. Preferred peptides to use as antigens arethe cytokine binding domain, disclosed herein, and zalpha11 hydrophilicpeptides such as those predicted by one of skill in the art from ahydrophobicity plot, determined for example, from a Hopp/Woodshydrophilicity profile based on a sliding six-residue window, withburied G, S, and T residues and exposed H, Y, and W residues ignored.For example, zalpha11 hydrophilic peptides include peptides comprisingamino acid sequences selected from the group consisting of: (1) aminoacid number 51 (Trp) to amino acid number 61 (Glu) of SEQ ID NO:2; (2)amino acid number 136 (Ile) to amino acid number 143 (Glu) of SEQ IDNO:2; (3) amino acid number 187 (Pro) to amino acid number 195 (Ser) ofSEQ ID NO:2; and (4) amino acid number 223 (Phe) to amino acid number232 (Glu) of SEQ ID NO:2. The corresponding hydrophilic regions inreference to SEQ ID NO:6 can be made with cross-reference to the aboveamino acid residues of SEQ ID NO:2. Moreover, antigenic epitope-bearingpolypeptides as predicted by a Jameson-Wolf plot, e.g., using DNASTARProtean program (DNASTAR, Inc., Madison, Wis.) are suitable antigens. Inaddition, conserved motifs, and variable regions between conservedmotifs of zalpha11 soluble receptor are suitable antigens. Suitableantigens also include the zalpha11 polypeptides disclosed above incombination with another class I cytokine extracellular domain, such asthose that form soluble zalpha11 heterodimeric polypeptides, such assoluble zalpha11/IL-2Rγ. Moreover, corresponding regions of the mousesoluble zalpha11 receptor polypeptide (residues 20 (Cys) to 237 (His)SEQ ID NO:12) can be used to generate antibodies against the solublemouse zalpha11 receptor. In addition Antibodies generated from thisimmune response can be isolated and purified as described herein.Methods for preparing and isolating polyclonal and monoclonal antibodiesare well known in the art. See, for example, Current Protocols inImmunology, Cooligan, et al. (eds.), National Institutes of Health, JohnWiley and Sons, Inc., 1995; Sambrook et al., Molecular Cloning: ALaboratory Manual, Second Edition, Cold Spring Harbor, N.Y., 1989; andHurrell, J. G. R., Ed., Monoclonal Hybridoma Antibodies: Techniques andApplications, CRC Press, Inc., Boca Raton, Fla., 1982.

As would be evident to one of ordinary skill in the art, polyclonalantibodies can be generated from inoculating a variety of warm-bloodedanimals such as horses, cows, goats, sheep, dogs, chickens, rabbits,mice, and rats with a soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ polypeptideor a fragment thereof. The immunogenicity of a zalpha11 polypeptide maybe increased through the use of an adjuvant, such as alum (aluminumhydroxide) or Freund's complete or incomplete adjuvant. Polypeptidesuseful for immunization also include fusion polypeptides, such asfusions of zalpha11 or a portion thereof with an immunoglobulinpolypeptide or with maltose binding protein. The polypeptide immunogenmay be a full-length molecule or a portion thereof. If the polypeptideportion is “hapten-like”, such portion may be advantageously joined orlinked to a macromolecular carrier (such as keyhole limpet hemocyanin(KLH), bovine serum albumin (BSA) or tetanus toxoid) for immunization.

As used herein, the term “antibodies” includes polyclonal antibodies,affinity-purified polyclonal antibodies, monoclonal antibodies, andantigen-binding fragments, such as F(ab′)₂ and Fab proteolyticfragments. Genetically engineered intact antibodies or fragments, suchas chimeric antibodies, Fv fragments, single chain antibodies and thelike, as well as synthetic antigen-binding peptides and polypeptides,are also included. Non-human antibodies may be humanized by graftingnon-human CDRs onto human framework and constant regions, or byincorporating the entire non-human variable domains (optionally“cloaking” them with a human-like surface by replacement of exposedresidues, wherein the result is a “veneered” antibody). In someinstances, humanized antibodies may retain non-human residues within thehuman variable region framework domains to enhance proper bindingcharacteristics. Through humanizing antibodies, biological half-life maybe increased, and the potential for adverse immune reactions uponadministration to humans is reduced.

Antibodies are considered to be specifically binding if: 1) they exhibita threshold level of binding activity, and 2) they do not significantlycross-react with related polypeptide molecules. A threshold level ofbinding is determined if anti-soluble zalpha11 receptor or anti-solublezalpha11 heterodimeric polypeptide, such as anti-soluble zalpha11/IL-2Rγantibodies herein bind to a soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγpolypeptide, peptide or epitope with an affinity at least 10-foldgreater than the binding affinity to control (non-soluble zalpha11receptor or soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ) polypeptide. It is preferred that the antibodiesexhibit a binding affinity (K_(a)) of 10⁶ M⁻¹ or greater, preferably 10⁷M⁻¹ or greater, more preferably 10⁸ M⁻¹ or greater, and most preferably10⁹ M⁻¹ or greater. The binding affinity of an antibody can be readilydetermined by one of ordinary skill in the art, for example, byScatchard analysis (Scatchard, G., Ann. NY Acad. Sci. 51: 660-672,1949).

Whether anti-soluble zalpha11 receptor or anti-soluble zalpha11heterodimeric polypeptide, such as anti-soluble zalpha11/IL-2Rγantibodies do not significantly cross-react with related polypeptidemolecules is shown, for example, by the antibody detecting solublezalpha11 receptor or soluble zalpha11 heterodimeric polypeptide, such assoluble zalpha11/IL-2Rγ polypeptide but not known related polypeptidesusing a standard Western blot analysis (Ausubel et al., ibid.). Examplesof known related polypeptides are those disclosed in the prior art, suchas known orthologs, and paralogs, and similar known members of a proteinfamily. Screening can also be done using non-human soluble zalpha11receptor or soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ, and soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ mutantpolypeptides. Moreover, antibodies can be “screened against” knownrelated polypeptides, to isolate a population that specifically binds tothe soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ polypeptides. For example,antibodies raised to soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ are adsorbedto related polypeptides adhered to insoluble matrix; antibodies specificto soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ will flow through thematrix under the proper buffer conditions. Screening allows isolation ofpolyclonal and monoclonal antibodies non-crossreactive to known closelyrelated polypeptides (Antibodies: A Laboratory Manual, Harlow and Lane(eds.), Cold Spring Harbor Laboratory Press, 1988; Current Protocols inImmunology, Cooligan, et al. (eds.), National Institutes of Health, JohnWiley and Sons, Inc., 1995). Screening and isolation of specificantibodies is well known in the art. See, Fundamental Immunology, Paul(eds.), Raven Press, 1993; Getzoff et al., Adv. in Immunol. 43: 1-98,1988; Monoclonal Antibodies: Principles and Practice, Goding, J. W.(eds.), Academic Press Ltd., 1996; Benjamin et al., Ann. Rev. Immunol.2: 67-101, 1984. Specifically binding anti-soluble zalpha11 receptor oranti-soluble zalpha11 heterodimeric polypeptide, such as anti-solublezalpha11/IL-2Rγ antibodies can be detected by a number of methods in theart, and disclosed below.

A variety of assays known to those skilled in the art can be utilized todetect antibodies that bind to soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγproteins or polypeptides. Exemplary assays are described in detail inAntibodies: A Laboratory Manual, Harlow and Lane (Eds.), Cold SpringHarbor Laboratory Press, 1988. Representative examples of such assaysinclude: concurrent immunoelectrophoresis, radioimmunoassay,radioimmuno-precipitation, enzyme-linked immunosorbent assay (ELISA),dot blot or Western blot assay, inhibition or competition assay, andsandwich assay. In addition, antibodies can be screened for binding towild-type versus mutant soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ protein orpolypeptide.

Alternative techniques for generating or selecting antibodies usefulherein include in vitro exposure of lymphocytes to soluble zalpha11receptor or soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ protein or peptide, and selection of antibody displaylibraries in phage or similar vectors (for instance, through use ofimmobilized or labeled soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ protein orpeptide). Genes encoding polypeptides having potential binding domainsfor soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ polypeptide, can beobtained by screening random peptide libraries displayed on phage (phagedisplay) or on bacteria, such as E. coli. Nucleotide sequences encodingthe polypeptides can be obtained in a number of ways, such as throughrandom mutagenesis and random polynucleotide synthesis. These randompeptide display libraries can be used to screen for peptides whichinteract with a known target which can be a protein or polypeptide, suchas a ligand or receptor, a biological or synthetic macromolecule, ororganic or inorganic substances. Techniques for creating and screeningsuch random peptide display libraries are known in the art (Ladner etal., U.S. Pat. No. 5,223,409; Ladner et al., U.S. Pat. No. 4,946,778;Ladner et al., U.S. Pat. No. 5,403,484 and Ladner et al., U.S. Pat. No.5,571,698) and random peptide display libraries and kits for screeningsuch libraries are available commercially, for instance from Clontech(Palo Alto, Calif.), Invitrogen Inc. (San Diego, Calif.), New EnglandBiolabs, Inc. (Beverly, Mass.) and Pharmacia LKB Biotechnology Inc.(Piscataway, N.J.). Random peptide display libraries can be screenedusing the soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ sequences disclosed hereinto identify proteins which bind to soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ.These “binding polypeptides” which interact with soluble zalpha11receptor or soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ polypeptides can be used for tagging cells; forisolating homolog polypeptides by affinity purification; they can bedirectly or indirectly conjugated to drugs, toxins, radionuclides andthe like. These binding polypeptides can also be used in analyticalmethods such as for screening expression libraries and neutralizingactivity, e.g., for blocking interaction between ligand and receptor, orviral binding to a receptor. The binding polypeptides can also be usedfor diagnostic assays for determining circulating levels of solublezalpha11 receptor or soluble zalpha11 heterodimeric polypeptide, such assoluble zalpha11/IL-2Rγ polypeptides; for detecting or quantitatingsoluble zalpha11 receptor or soluble zalpha11 heterodimeric polypeptide,such as soluble zalpha11/IL-2Rγ polypeptides as marker of underlyingpathology or disease. These binding polypeptides can also act aszalpha11 receptor or zalpha11 heterodimeric polypeptide, such aszalpha11/IL-2Rγ “antagonists” to block zalpha11 receptor or zalpha11heterodimeric polypeptide, such as zalpha11/IL-2Rγ binding and signaltransduction in vitro and in vivo. Again, these anti-soluble zalpha11receptor or anti-soluble zalpha11 heterodimeric polypeptide, such asanti-soluble zalpha11/IL-2Rγ binding polypeptides would be useful forinhibiting zalpha11 Ligand activity, as well as receptor activity orprotein-binding. Antibodies raised to the heterodimer or multimericcombinations of the present invention are preferred embodiments, as theymay act more specifically against the zalpha11 Ligand, or more potentlythan antibodies raised to only one subunit. Moreover, the antagonisticand binding activity of the antibodies of the present invention can beassayed in the zalpha11 Ligand proliferation and other biological assaysdescribed herein.

Antibodies to soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ may be usedfor tagging cells that express zalpha11 receptor or zalpha11heterodimeric polypeptides, such as zalpha11/IL-2Rγ; for isolatingsoluble zalpha11 receptor or soluble zalpha11 heterodimeric polypeptide,such as soluble zalpha11/IL-2Rγ polypeptide by affinity purification;for diagnostic assays for determining circulating levels of solublezalpha11 receptor or soluble zalpha11 heterodimeric polypeptide, such assoluble zalpha11/IL-2Rγ polypeptides; for detecting or quantitatingsoluble zalpha11 receptor or soluble zalpha11 heterodimeric polypeptide,such as soluble zalpha11/IL-2Rγ as marker of underlying pathology ordisease; in analytical methods employing FACS; for screening expressionlibraries; for generating anti-idiotypic antibodies; and as neutralizingantibodies or as antagonists to block zalpha11 receptor or zalpha11heterodimeric polypeptide, such as zalpha11/IL-2Rγ, or zalpha11 Ligandactivity in vitro and in vivo. Suitable direct tags or labels includeradionuclides, enzymes, substrates, cofactors, inhibitors, fluorescentmarkers, chemiluminescent markers, magnetic particles and the like;indirect tags or labels may feature use of biotin-avidin or othercomplement/anti-complement pairs as intermediates. Antibodies herein mayalso be directly or indirectly conjugated to drugs, toxins,radionuclides and the like, and these conjugates used for in vivodiagnostic or therapeutic applications. Moreover, antibodies to solublezalpha11 receptor or soluble zalpha11 heterodimeric polypeptide, such assoluble zalpha11/IL-2Rγ or fragments thereof may be used in vitro todetect denatured or non-denatured soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ orfragments thereof in assays, for example, Western Blots or other assaysknown in the art.

Antibodies to soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ are usefulfor tagging cells that express the corresponding receptors and assayingtheir expression levels, for affinity purification, within diagnosticassays for determining circulating levels of soluble receptorpolypeptides, analytical methods employing fluorescence-activated cellsorting. Moreover, divalent antibodies, and anti-idiotypic antibodiesmay be used as agonists to mimic the effect of the zalpha11 Ligand.

Antibodies herein can also be directly or indirectly conjugated todrugs, toxins, radionuclides and the like, and these conjugates used forin vivo diagnostic or therapeutic applications. For instance, antibodiesor binding polypeptides which recognize soluble zalpha11 receptor orsoluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ polypeptides of the present invention can be used toidentify or treat tissues or organs that express a correspondinganti-complementary molecule (i.e., a zalpha11 receptor, or zalpha11heterodimeric receptor, such as zalpha11/IL-2Rγ). More specifically,anti-soluble zalpha11 receptor or anti-soluble zalpha11 heterodimericpolypeptide, such as anti-soluble zalpha11/IL-2Rγ antibodies, orbioactive fragments or portions thereof, can be coupled to detectable orcytotoxic molecules and delivered to a mammal having cells, tissues ororgans that express the zalpha11 receptor or a zalpha11 heterodimericreceptor, such as zalpha11/IL-2Rγ receptor molecules.

Suitable detectable molecules may be directly or indirectly attached topolypeptides that bind soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ (“bindingpolypeptides,” including binding peptides disclosed above), antibodies,or bioactive fragments or portions thereof Suitable detectable moleculesinclude radionuclides, enzymes, substrates, cofactors, inhibitors,fluorescent markers, chemiluminescent markers, magnetic particles andthe like. Suitable cytotoxic molecules may be directly or indirectlyattached to the polypeptide or antibody, and include bacterial or planttoxins (for instance, diphtheria toxin, Pseudomonas exotoxin, ricin,abrin and the like), as well as therapeutic radionuclides, such asiodine-131, rhenium-188 or yttrium-90 (either directly attached to thepolypeptide or antibody, or indirectly attached through means of achelating moiety, for instance). Binding polypeptides or antibodies mayalso be conjugated to cytotoxic drugs, such as adriamycin. For indirectattachment of a detectable or cytotoxic molecule, the detectable orcytotoxic molecule can be conjugated with a member of acomplementary/anticomplementary pair, where the other member is bound tothe binding polypeptide or antibody portion. For these purposes,biotin/streptavidin is an exemplary complementary/anticomplementarypair.

In another embodiment, binding polypeptide-toxin fusion proteins orantibody-toxin fusion proteins can be used for targeted cell or tissueinhibition or ablation (for instance, to treat cancer cells or tissues).Alternatively, if the binding polypeptide has multiple functionaldomains (i.e., an activation domain or a ligand binding domain, plus atargeting domain), a fusion protein including only the targeting domainmay be suitable for directing a detectable molecule, a cytotoxicmolecule or a complementary molecule to a cell or tissue type ofinterest. In instances where the fusion protein including only a singledomain includes a complementary molecule, the anti-complementarymolecule can be conjugated to a detectable or cytotoxic molecule. Suchdomain-complementary molecule fusion proteins thus represent a generictargeting vehicle for cell/tissue-specific delivery of genericanti-complementary-detectable/cytotoxic molecule conjugates.

In another embodiment, soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ bindingpolypeptide-cytokine or antibody-cytokine fusion proteins can be usedfor enhancing in vivo killing of target tissues (for example, blood,lymphoid, colon, and bone marrow cancers), if the bindingpolypeptide-cytokine or anti-soluble zalpha11 receptor or anti-solublezalpha11 heterodimeric polypeptide, such as anti-soluble zalpha11/IL-2Rγantibody targets the hyperproliferative cell (See, generally, Hornick etal., Blood 89:4437-47, 1997). The described fusion proteins enabletargeting of a cytokine to a desired site of action, thereby providingan elevated local concentration of cytokine. Suitable anti-zalpha11homodimer and heterodimer antibodies target an undesirable cell ortissue (i.e., a tumor or a leukemia), and the fused cytokine mediatesimproved target cell lysis by effector cells. Suitable cytokines forthis purpose include interleukin 2 and granulocyte-macrophagecolony-stimulating factor (GM-CSF), for instance.

Alternatively, soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ bindingpolypeptide or antibody fusion proteins described herein can be used forenhancing in vivo killing of target tissues by directly stimulating azalpha11 receptor-modulated apoptotic pathway, resulting in cell deathof hyperproliferative cells expressing zalpha11 receptor or a zalpha11heterodimeric receptor, such as soluble zalpha11/IL-2Rγ receptor.

Four-helix bundle cytokines that bind to cytokine receptors as well asother proteins produced by activated lymphocytes play an importantbiological role in cell differentiation, activation, recruitment andhomeostasis of cells throughout the body. Therapeutic utility includestreatment of diseases that require immune regulation includingautoimmune diseases, such as, rheumatoid arthritis, multiple sclerosis,myasthenia gravis, systemic lupus erythomatosis and diabetes. Zalpha11Ligand antagonists, including soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ, maybe important in the regulation of inflammation, and therefore would beuseful in treating rheumatoid arthritis, asthma, ulcerative colitis,inflammatory bowel disease, Crohn's disease, and sepsis. There may be arole of zalpha11 Ligand antagonists, including soluble zalpha11 receptoror soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ, in mediating tumorgenesis, and therefore would beuseful in the treatment of cancer. Zalpha11 Ligand antagonists,including soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ, may be a potentialtherapeutic in suppressing the immune system that would be important forreducing graft rejection. Soluble zalpha11 receptor or soluble zalpha11heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγ may haveusefulness in prevention of graft vs. host disease.

Alternatively, zalpha11 Ligand antagonists, including soluble zalpha11receptor or soluble zalpha11 heterodimeric polypeptide, such as solublezalpha11/IL-2Rγ receptors in conjunction with other cytokines may enableselective activation, enhancement, or selective suppression, of theimmune system in conjunction with zalpha11 Ligand on other cytokineswhich would be important in boosting immunity to infectious diseases,treating immunocompromised patients, such as HIV+ patient, or inimproving vaccines. In particular, zalpha11 antagonists, includingsoluble zalpha11 receptor or soluble zalpha11 heterodimeric polypeptide,such as soluble zalpha11/IL-2Rγ, could prevent the expansion of a subsetof the immune system involving zalpha11 Ligand (e.g., NK cells andmature B-cells), while enabling expansion of progenitors induced byother cytokines (e.g., T-cells), and would provide therapeutic value intreatment of viral infection and other infection. For example, withDengue virus infection, which causes dengue hemorrhagic fever/DengueShock syndrome (DHF/DSS) it is believed that severe DHF/DSS occurs as aresult of “immune enhancement” i.e., enhanced replication of the virusin the presence of preexisting antibodies against another serotype. Inthe second infection by a different Dengue virus serotype, the immunesystem raises antibodies against the first virus that cross-react but donot neutralize the virus, and that potentially aid its entry intomacrophages. Thus, suppression of the antibody immune response, or Bcell response, during a second or third Dengue infection may help theimmune system react appropriately in the second infection to neutralizethe virus by suppressing the “enhancing” antibodies from the firstserotpye infection, and consequently avoiding severe DHF/DSS. Forreview, see White, D. O. and Fenner F. J. (Eds.) Medical Virology,3^(rd) ed., Academic Press, Orlando Fla., 1986, pages 479-508).Similarly, suppression of maternal antibody responses against fetalantigens by soluble receptors of the present invention can aid inpreventing birth defects and spontaneous abortion. Moreover, in suchapplications the soluble receptors of the present invention can be usedin conjunction with other cytokines to suppress some immune systemactivities (e.g., B-cell proliferation, using the soluble receptors) butallowing others to increase, e.g., in the presence of other cytokinesdescribed herein and known in the art.

The bioactive binding polypeptide or antibody conjugates describedherein can be delivered orally, intravenously, intraarterially orintraductally, or may be introduced locally at the intended site ofaction. For pharmaceutical use, the soluble zalpha11 receptor or solublezalpha11 heterodimeric polypeptide, such as soluble zalpha11/IL-2Rγreceptor polypeptides of the present invention are formulated forparenteral, particularly intravenous or subcutaneous, delivery accordingto conventional methods. Intravenous administration will be by bolusinjection or infusion over a typical period of one to several hours. Ingeneral, pharmaceutical formulations will include a zalpha11 solublereceptor polypeptide in combination with a pharmaceutically acceptablevehicle, such as saline, buffered saline, 5% dextrose in water or thelike. Formulations may further include one or more excipients,preservatives, solubilizers, buffering agents, albumin to preventprotein loss on vial surfaces, etc. Methods of formulation are wellknown in the art and are disclosed, for example, in Remington: TheScience and Practice of Pharmacy, Gennaro, ed., Mack Publishing Co.,Easton, Pa., 19th ed., 1995. Therapeutic doses will generally be in therange of 0.1 to 100 μg/kg of patient weight per day, preferably 0.5-20mg/kg per day, with the exact dose determined by the clinician accordingto accepted standards, taking into account the nature and severity ofthe condition to be treated, patient traits, etc. Determination of doseis within the level of ordinary skill in the art. The proteins may beadministered for acute treatment, over one week or less, often over aperiod of one to three days or may be used in chronic treatment, overseveral months or years. In general, a therapeutically effective amountof zalpha11 soluble receptor polypeptide is an amount sufficient toproduce a clinically significant effect.

The invention is further illustrated by the following non-limitingexamples.

EXAMPLES Example 1 Construction of Expression Vector ExpressingFull-Length Zalpha11

The entire zalpha11 receptor was isolated from a plasmid containingzalpha11 receptor cDNA (SEQ ID NO:1) using PCR with primers ZC19,905(SEQ ID NO:19) and ZC19,906 (SEQ ID NO:20). The reaction conditions wereas follows: 95° C. for 1 min; 35 cycles at 95° C. for 1 min, 55° C. for1 min, 72° C. for 2 min; followed by 72° C. at 10 min; then a 10° C.soak. The PCR product was run on a 1% low melting point agarose(Boerhinger Mannheim) gel and the approximately 1.5 kb zalpha11 cDNAisolated using Qiaquick™ gel extraction kit (Qiagen) as permanufacturer's instructions.

The purified zalpha11 cDNA was digested with BamHI (Boerhinger Mannheim)and EcoRI (BRL) as per manufacturer's instructions. The entire digestwas run on a 1% low melting point agarose (Boerhinger Mannheim) gel andthe cleaved zalpha11 fragment was purified the using Qiaquick™ gelextraction kit as per manufacturer's instructions. The resultant cleavedzalpha11 fragment was inserted into an expression vector as describedbelow.

Recipient expression vector pZP-5N was digested with BamHI (BoerhingerMannheim) and EcoRI (BRL) as per manufacturer's instructions, and gelpurified as described above. This vector fragment was combined with theBamHI and EcoRI cleaved zalpha11 fragment isolated above in a ligationreaction using T4 Ligase (BRL). The ligation was incubated at 15° C.overnight. A sample of the ligation was electroporated in to DH10BelectroMAX™ electrocompetent E. coli cells (25 μF, 200 Ω, 2.3V).Transformants were plated on LB+Ampicillin plates and single coloniesscreened by PCR to check for the zalpha11 sequence using ZC19,905 (SEQID NO:19) and ZC19,906 (SEQ ID NO:20) using the PCR conditions asdescribed above. Confirmation of the zalpha11 sequence was made bysequence analysis. The insert was approximately 1.6 kb, and wasfull-length.

Example 2 Zalpha11 Based Proliferation in BAF3 Assay Using Alamar Blue

BaF3 cells expressing the full-length zalpha11 receptor wereconstructed, using the zalpha11 expression vector, described inExample 1. The BaF3 cells expressing the zalpha11 receptor mRNA weredesignated BaF3/zalpha11. These cells provide an assay system fordetecting zalpha11 Ligand activity as described in numerous Examplesbelow. Conversely, these cells provide also an assay system fordetecting zalpha11 Ligand antagonist or inhibitory activity by thesoluble receptors and antibodies of the present invention.

A. Construction of BaF3 Cells Expressing Human Zalpha11 Receptor

BaF3, an interleukin-3 (IL-3) dependent pre-lymphoid cell line derivedfrom murine bone marrow (Palacios and Steinmetz, Cell 41: 727-734, 1985;Mathey-Prevot et al., Mol. Cell. Biol. 6: 4133-4135, 1986), wasmaintained in complete media (RPMI medium (JRH Bioscience Inc., Lenexa,Kans.) supplemented with 10% heat-inactivated fetal calf serum, 2 ng/mlmurine IL-3 (mIL-3) (R & D, Minneapolis, Minn.), 2 mM L-glutaMax-1™(Gibco BRL), 1 mM Sodium Pyruvate (Gibco BRL), and PSN antibiotics(GIBCO BRL)). Prior to electroporation, pZP-5N/zalpha11 plasmid DNA(Example 1) was prepared and purified using a Qiagen Maxi Prep kit(Qiagen) as per manufacturer's instructions. BaF3 cells forelectroporation were washed once in RPMI media and then resuspended inRPMI media at a cell density of 10⁷ cells/ml. One ml of resuspended BaF3cells was mixed with 30 μg of the pZP-5N/zalpha11 plasmid DNA andtransferred to separate disposable electroporation chambers (GIBCO BRL).Following a 15 minute incubation at room temperature the cells weregiven two serial shocks (800 lFad/300 V.; 1180 lFad/300 V.) delivered byan electroporation apparatus (CELL-PORATOR™; GIBCO BRL). After a 5minute recovery time, the electroporated cells were transferred to 50 mlof complete media and placed in an incubator for 15-24 hours (37° C., 5%CO₂). The cells were then spun down and resuspended in 50 ml of completemedia containing Geneticin™ (Gibco) selection (500 μg/ml G418) in aT-162 flask to isolate the G418-resistant pool. Pools of the transfectedBaF3 cells, hereinafter called BaF3/zalpha11 cells, were assayed forsignaling capability as described below.

B. Testing the Signaling Capability of the BaF3/Zalpha11 Cells Using anAlamar Blue Proliferation Assay

BaF3/zalpha11 cells were spun down and washed in the complete media,described above, but without mIL-3 (hereinafter referred to as “mIL-3free media”). The cells were spun and washed 3 times to ensure theremoval of the mIL-3. Cells were then counted in a hemacytometer. Cellswere plated in a 96-well format at 5000 cells per well in a volume of100 μl per well using the mIL-3 free media.

Proliferation of the BaF3/zalpha11 cells was assessed using conditionedmedia from zalpha11 Ligand-expressing cells diluted with mIL-3 freemedia to 50%, 25%, 12.5%, 6.25%, 3.125%, 1.5%, 0.75% and 0.375%concentrations; or purified zalpha11 Ligand (commonly owned U.S. patentapplication Ser. No. 09/522,217) diluted with mIL-3 free media to 500ng/ml, 250 ng/ml, 125 ng/ml, 62 ng/ml, 30 ng/ml, 15 ng/ml, 7.5 ng/ml,3.75 ng/ml, 1.8 ng/ml, 0.9 ng/ml, 0.5 ng/ml and 0.25 ng/mlconcentrations. 100 μl of the diluted mTPO was added to theBaF3/zalpha11 cells. The total assay volume is 200 μl. Negative controlswere run in parallel using mIL-3 free media only. The assay plates wereincubated at 37° C., 5% CO₂ for 3 days at which time Alamar Blue(Accumed, Chicago, Ill.) was added at 20 μl/well. Alamar Blue gives afluourometric readout based on the metabolic activity of cells, and isthus a direct measurement of cell proliferation in comparison to anegative control. Plates were again incubated at 37° C., 5% CO₂ for 24hours. Plates were read on the Fmax™ plate reader (Molecular DevicesSunnyvale, Calif.) using the SoftMax™ Pro program, at wavelengths 544(Excitation) and 590 (Emmission). Results confirmed the signalingcapability of the zalpha11 receptor, as the zalpha11 Ligandsignificantly induced proliferation over over background levels.

Example 3 Screening for Zalpha11 Ligand Using BaF3/Zalpha11 Cells Usingan Alamar Blue Proliferation Assay

A. Activation of Primary Monkey Splenocytes to Test for Presence ofZalpha11 Ligand

Monkey splenocytes were stimulated in vitro to produce conditioned mediato test for the presence of zalpha11 Ligand activity as described below.Monkey spleens were obtained from 8 year old female M. nesestrianmonkeys. The spleens were teased part to produce a single cellsuspension. The mononuclear cells were isolated by Ficoll-Paque® PLUS(Pharmacia Biotech, Uppsala, Sweden) density gradient. The mononuclearcells were seeded at 2×10⁶ cells/ml in RPMI-1640 media supplemented with10% FBS and activated with with 5 ng/ml Phorbol-12-myristate-13-acetate(PMA) (Calbiochem, San Diego, Calif.), and 0.5 mg/ml Ionomycin™(Calbiochem) for 48 h. The supernatant from the stimulated monkey spleencells was used to assay proliferation of the BaF3/zalpha11 cells asdescribed below.

B. Screening for Zalpha11 Ligand Using BaF3/Zalpha11 Cells Using anAlamar Blue Proliferation Assay

BaF3/Zalpha11 cells were spun down and washed in mIL-3 free media. Thecells were spun and washed 3 times to ensure the removal of the mIL-3.Cells were then counted in a hemacytometer. Cells were plated in a96-well format at 5000 cells per well in a volume of 100 μl per wellusing the mIL-3 free media.

Proliferation of the BaF3/Zalpha11 cells was assessed using conditionedmedia from activated monkey spleen (see Example 3A). Conditioned mediawas diluted with mIL-3 free media to 50%, 25%, 12.5%, 6.25%, 3.125%,1.5%, 0.75% and 0.375% concentrations. 100 μl of the diluted conditionedmedia was added to the BaF3/Zalpha11 cells. The total assay volume is200 μl. The assay plates were incubated at 37° C., 5% CO₂ for 3 days atwhich time Alamar Blue (Accumed, Chicago, Ill.) was added at 20 μl/well.Plates were again incubated at 37° C., 5% CO₂ for 24 hours. Plates wereread on the Fmax™ plate reader (Molecular devices) as described above(Example 2).

Results confirmed the proliferative response of the BaF3/Zalpha11 cellsto a factor present in the activated monkey spleen conditioned media.The response, as measured, was approximately 4-fold over background atthe 50% concentration. The untransfected BaF3 cells did not proliferatein response to this factor, showing that this factor is specific for theZalpha11 receptor.

C. Human Primary Source Used to Isolate Zalpha11 Ligand

100 ml blood draws were taken from each of six donors. The blood wasdrawn using 10×10 ml vacutainer tubes containing heparin. Blood waspooled from six donors (600 ml), diluted 1:1 in PBS, and separated usinga Ficoll-Paque® PLUS (Pharmacia Biotech). The isolated primary humancell yield after separation on the ficoll gradient was 1.2×10⁹ cells.

Cells were suspended in 9.6 ml MACS buffer (PBS, 0.5% EDTA, 2 mM EDTA).1.6 ml of cell suspension was removed and 0.4 ml CD3 microbeads(Miltenyi Biotec, Auburn, Calif.) added. The mixture was incubated for15 min. at 4° C. These cells labeled with CD3 beads were washed with 30ml MACS buffer, and then resuspended in 2 ml MACS buffer.

A VS+ column (Miltenyi) was prepared according to the manufacturer'sinstructions. The VS+ column was then placed in a VarioMACS™ magneticfield (Miltenyi). The column was equilibrated with 5 ml MACS buffer. Theisolated primary human cells were then applied to the column. The CD3negative cells were allowed to pass through. The column was rinsed with9 ml (3×3 ml) MACS buffer. The column was then removed from the magnetand placed over a 15 ml falcon tube. CD3+ cells were eluted by adding 5ml MACS buffer to the column and bound cells flushed out using theplunger provided by the manufacturer. The incubation of the cells withthe CD3 magnetic beads, washes, and VS+ column steps (incubation throughelution) above were repeated five more times. The resulting CD3+fractions from the six column separations were pooled. The yield of CD3+selected human cells were 3×10⁸ total cells.

A sample of the pooled CD3+ selected human cells was removed forstaining and sorting on a fluorescent antibody cell sorter (FACS) toassess their purity. The human CD3+ selected cells were 91% CD3+ cells.

The human CD3+ selected cells were activated by incubating in RPMI+5%FBS+PMA 10 ng/ml and Ionomycin 0.5 μg/ml (Calbiochem) for 13 hours 37°C. The supernatant from these activated CD3+ selected human cells wastested for zalpha11 Ligand activity as described below. Moreover, theactivated CD3+ selected human cells were used to prepare a cDNA library,as described in commonly owned U.S. patent application Ser. No.09/522,217.

D. Testing Supernatant from Activated CD3+ Selected Human Cells forZalpha11 Ligand Using BaF3/Zalpha11 Cells and an Alamar BlueProliferation Assay

BaF3/Zalpha11 cells were spun down and washed in mIL-3 free media. Thecells were spun and washed 3 times to ensure the removal of the mIL-3.Cells were then counted in a hemacytometer. Cells were plated in a96-well format at 5000 cells per well in a volume of 100 μl per wellusing the mIL-3 free media.

Proliferation of the BaF3/Zalpha11 cells was assessed using conditionedmedia from activated CD3+ selected human cells (see Example 5C) dilutedwith mIL-3 free media to 50%, 25%, 12.5%, 6.25%, 3.125%, 1.5%, 0.75% and0.375% concentrations. 100 μl of the diluted conditioned media was addedto the BaF3/Zalpha11 cells. The total assay volume is 200 μl. The assayplates were incubated and assayed as described in Example 5B.

Results confirmed the proliferative response of the BaF3/Zalpha11 cellsto a factor present in the activated CD3+ selected human cellconditioned media. The response, as measured, was approximately 10-foldover background at the 50% concentration. The untransfected BaF3 cellsdid not proliferate in response to this factor, showing that this factoris specific for the Zalpha11 receptor. Moreover soluble zalpha11receptor blocked this proliferative activity in the BaF3/Zalpha11 cells(see, Example 16).

Example 4 Construction of Mammalian Expression Vectors that ExpressZalpha11 Soluble Receptors: Zalpha11CEE, Zalpha11CFLG, Zalpha11CHIS andZalph11-Fc4

A. Construction of Zalpha11 Mammalian Expression Vector ContainingZalph11CEE, Zalph11CFLG and Zalph11CHIS

An expression vector was prepared for the expression of the soluble,extracellular domain of the zalpha11 polypeptide, pC4zalph11CEE, whereinthe construct is designed to express a zalpha11 polypeptide comprised ofthe predicted initiating methionine and truncated adjacent to thepredicted transmembrane domain, and with a C-terminal Glu-Glu tag (SEQID NO:14).

A 700 bp PCR generated zalpha11 DNA fragment was created using ZC19,931(SEQ ID NO:21) and ZC19,932 (SEQ ID NO:22) as PCR primers to add Asp718and BamHI restriction sites. A plasmid containing the zalpha11 receptorcDNA (SEQ ID NO:1) was used as a template. PCR amplification of thezalpha11 fragment was performed as follows: Twenty five cycles at 94 C.for 0.5 minutes; five cycles at 94° C. for 10 seconds, 50° C. for 30seconds, 68° C. for 45 seconds, followed by a 4° C. hold. The reactionwas purified by chloroform/phenol extraction and isopropanolprecipitation, and digested with Asp718 and BamHI (Gibco BRL) followingmanufacturer's protocol. A band of the predicted size, 700 bp, wasvisualized by 1% agarose gel electrophoresis, excised and the DNA waspurified using a QiaexII™ purification system (Qiagen) according themanufacturer's instructions.

The excised DNA was subcloned into plasmid pC4EE which had been cut withBamHI and Asp718. The pC4zalph11CEE expression vector uses the nativezalpha11 signal peptide and attaches the Glu-Glu tag (SEQ ID NO:14) tothe C-terminus of the zalpha11 polypeptide-encoding polynucleotidesequence. Plasmid pC4EE, is a mammalian expression vector containing anexpression cassette having the mouse metallothionein-1 promoter,multiple restriction sites for insertion of coding sequences, a stopcodon and a human growth hormone terminator. The plasmid also has an E.coli origin of replication, a mammalian selectable marker expressionunit having an SV40 promoter, enhancer and origin of replication, a DHFRgene and the SV40 terminator.

About 30 ng of the restriction digested zalpha11 insert and about 12 ngof the digested vector were ligated overnight at 16° C. One microliterof each ligation reaction was independently electroporated into DH10Bcompetent cells (GIBCO BRL, Gaithersburg, Md.) according tomanufacturer's direction and plated onto LB plates containing 50 mg/mlampicillin, and incubated overnight. Colonies were screened byrestriction analysis of DNA prepared from 2 ml liquid cultures ofindividual colonies. The insert sequence of positive clones was verifiedby sequence analysis. A large scale plasmid preparation was done using aQIAGEN® Maxi prep kit (Qiagen) according to manufacturer's instructions.

The same process was used to prepare the zalpha11 soluble receptors witha C-terminal his tag, composed of 6 His residues in a row; and aC-terminal flag (SEQ ID NO:23) tag, zalpha11 CFLAG. To construct theseconstructs, the aforementioned vector has either the HIS or the FLAG®tag in place of the glu-glu tag (SEQ ID NO:14).

B. Mammalian Expression Construction of Soluble Zalpha11 ReceptorZalpha11-Fc4

An expression plasmid containing all or part of a polynucleotideencoding zalpha11 was constructed via homologous recombination. Afragment of zalpha11 cDNA was isolated using PCR that includes thepolynucleotide sequence from extracellular domain of the zalpha11receptor. The two primers used in the production of the zalpha11fragment were: (1) The primers for PCR each include from 5′ to 3′ end:40 bp of the vector flanking sequence (5′ of the insert) and 17 bpcorresponding to the 5′ end of the zalpha11 extracellular domain (SEQ IDNO:24); and (2) 40 bp of the 5′ end of the Fc4 polynucleotide sequence(SEQ ID NO:25) and 17 bp corresponding to the 3′ end of the zalpha11extracellular domain (SEQ ID NO:26). The fragment of Fc4 for fusion withthe zalpha11 was generated by PCR in a similar fashion. The two primersused in the production of the Fc4 fragment were: (1) a 5′ primerconsisting of 40 bp of sequence from the 3′ end of zalpha11extracellular domain and 17 bp of the 5′ end of Fc4 (SEQ ID NO:27); and(2) a 3′ primer consisting of 40 bp of vector sequence (3′ of theinsert) and 17 bp of the 3′ end of Fc4 (SEQ ID NO:28).

PCR amplification of the each of the reactions described above wasperformed as follows: one cycle at 94° C. for 2 minutes; twenty-fivecycles at 94° C. for 30 seconds, 60° C. for 30 seconds, 72° C. for 1minute; one cycle at 72° C. for 5 minutes; followed by a 4° C. hold. Tenμl of the 100 μl PCR reaction was run on a 0.8% LMP agarose gel(Seaplaque GTG) with 1× TBE buffer for analysis. The remaining 90 μl ofPCR reaction is precipitated with the addition of 5 μl 1 M NaCl and 250μl of absolute ethanol. The expression vector used was derived from theplasmid pCZR199 (deposited at the American Type Culture Collection,10801 University Boulevard, Manassas, Va. 20110-2209, designated No.98668), and was cut with SmaI (BRL). The expression vector was derivedfrom the plasmid pCZR199, and is a mammalian expression vectorcontaining an expression cassette having the CMV immediate earlypromoter, a consensus intron from the variable region of mouseimmunoglobulin heavy chain locus, multiple restriction sites forinsertion of coding sequences, a stop codon and a human growth hormoneterminator. The expression vector also has an E. coli origin ofreplication, a mammalian selectable marker expression unit having anSV40 promoter, enhancer and origin of replication, a DHFR gene and theSV40 terminator. The expression vector used was constructed from pCZR199by the replacement of the metallothionein promoter with the CMVimmediate early promoter.

One hundred microliters of competent yeast cells (S. cerevisiae) werecombined with 10 μl containing approximately 1 μg each of the zalpha11and Fc4 inserts, and 100 ng of SmaI (BRL) digested expression vector andtransferred to a 0.2 cm electroporation cuvette. The yeast/DNA mixtureswere electropulsed at 0.75 kV (5 kV/cm), “infinite” ohms, 25 μF. To eachcuvette is added 600 μl of 1.2 M sorbitol and the yeast was plated intwo 300 μl aliquots onto two URA-D plates and incubated at 30° C.

After about 48 hours, the Ura+ yeast transformants from a single platewere resuspended in 1 ml H₂O and spun briefly to pellet the yeast cells.The cell pellet was resuspended in 1 ml of lysis buffer (2% TritonX-100, 1% SDS, 100 mM NaCl, 10 mM Tris, pH 8.0, 1 mM EDTA). Five hundredmicroliters of the lysis mixture was added to an Eppendorf tubecontaining 300 μl acid washed glass beads and 200 μl phenol-chloroform,vortexed for 1 minute intervals two or three times, followed by a 5minute spin in a Eppendorf centrifuge at maximum speed. Three hundredmicroliters of the aqueous phase was transferred to a fresh tube, andthe DNA precipitated with 600 μl ethanol (EtOH), followed bycentrifugation for 10 minutes at 4° C. The DNA pellet was resuspended in100 μl H₂O.

Transformation of electrocompetent E. coli cells (DH10B, GibcoBRL) isdone with 0.5-2 ml yeast DNA prep and 40 ul of DH10B cells. The cellswere electropulsed at 2.0 kV, 25 mF and 400 ohms. Followingelectroporation, 1 ml SOC (2% Bacto® Tryptone (Difco, Detroit, Mich.),0.5% yeast extract (Difco), 10 mM NaCl, 2.5 mM KCl, 10 mM MgCl2, 10 mMMgSO4, 20 mM glucose) was plated in 250 μl aliquots on four LB AMPplates (LB broth (Lennox), 1.8% Bacto Agar (Difco), 100 mg/LAmpicillin).

Individual clones harboring the correct expression construct forzalpha11-Fc4 were identified by restriction digest to verify thepresence of the zalpha11-Fc4 insert and to confirm that the various DNAsequences have been joined correctly to one another. The insert ofpositive clones were subjected to sequence analysis. Larger scaleplasmid DNA is isolated using the Qiagen Maxi kit (Qiagen) according tomanufacturer's instructions.

Example 5 Transfection and Expression of Zalpha11 Soluble ReceptorPolypeptides

BHK 570 cells (ATCC No. CRL-10314), passage 27, were plated at 1.2×10⁶cells/well (6-well plate) in 800 μl of serum free (SF) DMEM media (DMEM,Gibco/BRL High Glucose) (Gibco BRL, Gaithersburg, Md.). The cells weretransfected with expression plasmids containing zalpha11CEE,zalpha11CFLG or zalpha11CHIS described above (see, Example 4), usingLipofectin™ (Gibco BRL), in serum free (SF) DMEM. Three micrograms ofzalpha11CEE, zalpha11CFLG or zalpha11CHIS each were separately dilutedinto 1.5 ml tubes to a total final volume of 100 μl SF DMEM. In separatetubes, 15 μl of Lipofectin™ (Gibco BRL) was mixed with 100 μl of SFDMEM. The Lipofectin™ mix was incubated at room temperature for 30-45minutes then the DNA mix was added and allowed to incubate approximately10-15 minutes at room temperature.

The entire DNA: Lipofectin™ mixture was added to the plated cells anddistributed evenly over them. The cells were incubated at 37° C. forapproximately five hours, then transferred to separate 150 mm MAXIplates in a final volume of 30 ml DMEM/5% fetal bovine serum (FBS)(Hyclone, Logan, Utah). The plates were incubated at 37° C., 5% CO₂,overnight and the DNA: Lipofectin™ mixture was replaced with selectionmedia (5% FBS/DMEM with 1 μM methotrexate (MTX) the next day.

Approximately 10-12 days post-transfection, the plates were washed with10 ml SF DMEM. The wash media was aspirated and replaced with 7.25 mlserum-free DMEM. Sterile Teflon meshes (Spectrum Medical Industries, LosAngeles, Calif.) pre-soaked in SF DMEM were then placed over the clonalcell colonies. A sterile nitrocellulose filter pre-soaked in SF DMEM wasthen placed over the mesh. Orientation marks on the nitrocellulose weretransferred to the culture dish. The plates were then incubated for 5-6hours in a 37° C., 5% CO₂ incubator.

Following incubation, the filters/meshes were removed, and the mediaaspirated and replaced with 5% FBS/DMEM with 1 μM MTX. The filters werethen blocked in 10% nonfat dry milk/Western A buffer (Western A: 50 mMTris pH 7.4, 5 mM EDTA, 0.05% NP-40, 150 mM NaCl and 0.25% gelatin) for15 minutes at room temperature on a rotating shaker. The filters werethen incubated with an anti-Glu-Glu, anti-FLAG®, or anti-HISantibody-HRP conjugates, respectively, in 2.5% nonfat dry milk/Western Abuffer for one hour at room temperature on a rotating shaker. Thefilters were then washed three times at room temperature with Western Afor 5-10 minutes per wash. The filters were developed with ultra ECLreagent (Amersham Corp., Arlington Heights, Ill.) according themanufacturer's directions and visualized on the Lumi-Imager (RocheCorp.)

Positive expressing clonal colonies were mechanically picked to 12-wellplates in one ml of 5% FCS/DMEM with 5 μM MTX, then grown to confluence.Conditioned media samples were then tested for expression levels viaSDS-PAGE and Western analysis. The three highest expressing clones foreach construct were picked; two out of three were frozen down as back upand one was expanded for mycoplasma testing and large-scale factoryseeding.

B. Mammalian Expression of Soluble Zalpha11 Receptor Zalpha11-Fc4

BHK 570 cells (ATCC NO: CRL-10314) were plated in 10 cm tissue culturedishes and allowed to grow to approximately 50 to 70% confluencyovernight at 37□ C., 5% CO₂, in DMEM/FBS media (DMEM, Gibco/BRL HighGlucose, (Gibco BRL, Gaithersburg, Md.), 5% fetal bovine serum (Hyclone,Logan, Utah), 1 mM L-glutamine (JRH Biosciences, Lenexa, Kans.), 1 mMsodium pyruvate (Gibco BRL)). The cells were then transfected with theplasmid containing zalpha11-Fc4 (see, Example 9), using Lipofectamine™(Gibco BRL), in serum free (SF) media formulation (DMEM, 10 mg/mltransferrin, 5 mg/ml insulin, 2 mg/ml fetuin, 1% L-glutamine and 1%sodium pyruvate). The plasmid containing zalpha11-Fc4 was diluted into15 ml tubes to a total final volume of 640 ml with SF media. 35 ml ofLipofectamine™ (Gibco BRL) was mixed with 605 ml of SF medium. TheLipofectamine™mix was added to the DNA mix and allowed to incubateapproximately 30 minutes at room temperature. Five milliliters of SFmedia was added to the DNA:Lipofectamine™ mixture. The cells were rinsedonce with 5 ml of SF media, aspirated, and the DNA:Lipofectamine™mixture is added. The cells were incubated at 37° C. for five hours,then 6.4 ml of DMEM/10% FBS, 1% PSN media was added to each plate. Theplates were incubated at 37° C. overnight and the DNA:Lipofectamine™mixture was replaced with fresh 5% FBS/DMEM media the next day. On day 2post-transfection, the cells were split into the selection media(DMEM/FBS media from above with the addition of 1 mM methotrexate (SigmaChemical Co., St. Louis, Mo.)) in 150 mm plates at 1:10, 1:20 and 1:50.The media on the cells was replaced with fresh selection media at day 5post-transfection. Approximately 10 days post-transfection, two 150 mmculture dishes of methotrexate resistant colonies from each transfectionwere trypsinized and the cells are pooled and plated into a T-162 flaskand transferred to large scale culture.

Example 6 Purification of Zalpha11 Soluble Receptors from BHK 570 Cells

A. Purification of Zalpha11CEE Polypeptide from BHK 570

Unless otherwise noted, all operations were carried out at 4° C. Thefollowing procedure was used for purifying zalpha11 polypeptidecontaining C-terminal GluGlu (EE) tags. Thirty liters of cell factoryconditioned media was concentrated to 1.6 liters with an Amicon S10Y3spiral cartridge on a ProFlux A30. A Protease inhibitor solution wasadded to the concentrated 1.6 liters of cell factory conditioned mediafrom transfected BHK 570 cells (Example 5) to final concentrations of2.5 mM ethylenediaminetetraacetic acid (EDTA, Sigma Chemical Co. St.Louis, Mo.), 0.003 mM leupeptin (Boehringer-Mannheim, Indianapolis,Ind.), 0.001 mM pepstatin (Boehringer-Mannheim) and 0.4 mM Pefabloc(Boehringer-Mannheim). Samples were removed for analysis and the bulkvolume was frozen at −80° C. until the purification was started. Totaltarget protein concentrations of the concentrated cell factoryconditioned media was determined via SDS-PAGE and Western blot analysiswith the anti-EE HRP conjugated antibody.

A 100 ml column of anti-EE G-Sepharose (prepared as described below) waspoured in a Waters AP-5, 5 cm×10 cm glass column. The column was flowpacked and equilibrated on a BioCad Sprint (PerSeptive BioSystems,Framingham, Mass.) with phosphate buffered saline (PBS) pH 7.4. Theconcentrated cell factory conditioned media was thawed, 0.2 micronsterile filtered, pH adjusted to 7.4, then loaded on the columnovernight with 1 ml/minute flow rate. The column was washed with 10column volumes (CVs) of phosphate buffered saline (PBS, pH 7.4), thenplug eluted with 200 ml of PBS (pH 6.0) containing 0.5 mg/ml EE peptide(Anaspec, San Jose, Calif.) at 5 ml/minute. The EE peptide used has thesequence EYMPME (SEQ ID NO:14). The column was washed for 10 CVs withPBS, then eluted with 5 CVs of 0.2 M glycine, pH 3.0. The pH of theglycine-eluted column was adjusted to 7.0 with 2 CVs of 5×PBS, thenequilibrated in PBS (pH 7.4). Five ml fractions were collected over theentire elution chromatography and absorbance at 280 and 215 nM weremonitored; the pass through and wash pools were also saved and analyzed.The EE-polypeptide elution peak fractions were analyzed for the targetprotein via SDS-PAGE Silver staining and Western Blotting with theanti-EE HRP conjugated antibody. The polypeptide elution fractions ofinterest were pooled and concentrated from 60 ml to 5.0 ml using a10,000 Dalton molecular weight cutoff membrane spin concentrator(Millipore, Bedford, Mass.) according to the manufacturer'sinstructions.

To separate zalpha11CEE from other co-purifying proteins, theconcentrated polypeptide elution pooled fractions were subjected to aPOROS HQ-50 (strong anion exchange resin from PerSeptive BioSystems,Framingham, Mass.) at pH 8.0. A 1.0×6.0 cm column was poured and flowpacked on a BioCad Sprint. The column was counter ion charged thenequibrated in 20 mM TRIS pH 8.0 (Tris (Hydroxymethyl Aminomethane)). Thesample was diluted 1:13 (to reduce the ionic strength of PBS) thenloaded on the Poros HQ column at 5 ml/minute. The column was washed for10 CVs with 20 mM Tris pH 8.0 then eluted with a 40 CV gradient of 20 mMTris/1 M sodium chloride (NaCl) at 10 ml/minute. 1.5 ml fractions werecollected over the entire chromatography and absorbance at 280 and 215nM were monitored. The elution peak fractions were analyzed via SDS-PAGESilver staining. Fractions of interest were pooled and concentrated to1.5-2 ml using a 10,000 Dalton molecular weight cutoff membrane spinconcentrator (Millipore, Bedford, Mass.) according to the manufacturer'sinstructions.

To separate zalpha11CEE polypeptide from free EE peptide and anycontaminating co-purifying proteins, the pooled concentrated fractionswere subjected to chromatography on a 1.5×90 cm Sephadex S200(Pharmacia, Piscataway, N.J.) column equilibrated and loaded in PBS at aflow rate of 1.0 ml/min using a BioCad Sprint. 1.5 ml fractions werecollected across the entire chromatography and the absorbance at 280 and215 nM were monitored. The peak fractions were characterized viaSDS-PAGE Silver staining, and only the most pure fractions were pooled.This material represented purified zalpha11CEE polypeptide.

This purified material was finally subjected to a 4 ml ActiClean Etox(Sterogene) column to remove any remaining endotoxins. The sample waspassed over the PBS equilibrated gravity column four times then thecolumn was washed with a single 3 ml volume of PBS, which was pooledwith the “cleaned” sample. The material was then 0.2 micron sterilefiltered and stored at −80° C. until it was aliquoted.

On Western blotted, Coomassie Blue and Silver stained SDS-PAGE gels, thezalpha11CEE polypeptide was one major band of an apparent molecularweight of 50,000 Daltons. The mobility of this band was the same onreducing and non-reducing gels.

The protein concentration of the purified material was performed by BCAanalysis (Pierce, Rockford, Ill.) and the protein was aliquoted, andstored at −80° C. according to our standard procedures. On IEF(isoelectric focusing) gels the protein runs with a PI of less than 4.5.The concentration of zalpha11CEE polypeptide was 1.0 mg/ml.

Purified zalpha11CEE polypeptide was prepared for injection into rabbitsand sent to R & R Research and Development (Stanwood, Wash.) forantibody production. Rabbits were injected to produceanti-huzalpha11-CEE-BHK serum (Example 10, below).

To prepare anti-EE Sepharose, a 100 ml bed volume of protein G-Sepharose(Pharmacia, Piscataway, N.J.) was washed 3 times with 100 ml of PBScontaining 0.02% sodium azide using a 500 ml Nalgene 0.45 micron filterunit. The gel was washed with 6.0 volumes of 200 mM triethanolamine, pH8.2 (TEA, Sigma, St. Louis, Mo.), and an equal volume of EE antibodysolution containing 900 mg of antibody was added. After an overnightincubation at 4° C., unbound antibody was removed by washing the resinwith 5 volumes of 200 mM TEA as described above. The resin wasresuspended in 2 volumes of TEA, transferred to a suitable container,and dimethylpimilimidate-2HCl (Pierce, Rockford, Ill.) dissolved in TEA,was added to a final concentration of 36 mg/ml of protein G-Sepharosegel. The gel was rocked at room temperature for 45 min and the liquidwas removed using the filter unit as described above. Nonspecific siteson the gel were then blocked by incubating for 10 min. at roomtemperature with 5 volumes of 20 mM ethanolamine in 200 mM TEA. The gelwas then washed with 5 volumes of PBS containing 0.02% sodium azide andstored in this solution at 4° C.

B. Purification of Zalpha11CFLAG Polypeptide from BHK 570

Unless otherwise noted, all operations were carried out at 4° C. Thefollowing procedure was used for purifying zalpha11 polypeptidecontaining C-terminal FLAG® (FLG) (Sigma-Aldrich Co.) tags. Thirtyliters of cell factory conditioned media was concentrated to 1.7 literswith an Amicon S10Y3 spiral cartridge on a ProFlux A30. A Proteaseinhibitor solution was added to the 1.7 liters of concentrated cellfactory conditioned media from transfected BHK 570 cells (see, Example5) to final concentrations of 2.5 mM ethylenediaminetetraacetic acid(EDTA, Sigma Chemical Co. St. Louis, Mo.), 0.003 mM leupeptin(Boehringer-Mannheim, Indianapolis, Ind.), 0.001 mM pepstatin(Boehringer-Mannheim) and 0.4 mM Pefabloc (Boehringer-Mannheim). Sampleswere removed for analysis and the bulk volume was frozen at −80° C.until the purification was started. Total target protein concentrationsof the cell factory conditioned media was determined via SDS-PAGE andWestern blot analysis with the anti-FLAG (Kodak) HRP conjugatedantibody. A 125 ml column of anti-FLAG® M2-Agarose affinity gel(Sigma-Aldrich Co.) was poured in a Waters AP-5, 5 cm×10 cm glasscolumn. The column was flow packed and equilibrated on a BioCad Sprint(PerSeptive BioSystems, Framingham, Mass.) with phosphate bufferedsaline (PBS) pH 7.4. The concentrated cell factory conditioned media wasthawed, 0.2 micron sterile filtered, pH adjusted to 7.4, then loaded onthe column overnight with 1 ml/minute flow rate. The column was washedwith 10 column volumes (CVs) of phosphate buffered saline (PBS, pH 7.4),then plug eluted with 250 ml of PBS (pH 6.0) containing 0.5 mg/ml FLAG®(Sigma-Aldrich Co.) peptide at 5 ml/minute. The FLAG® peptide used hasthe sequence DYKDDDDK (SEQ ID NO:23). The column was washed for 10 CVswith PBS, then eluted with 5 CVs of 0.2 M glycine, pH 3.0. The pH of theglycine-eluted column was adjusted to 7.0 with 2 CVs of 5×PBS, thenequilibrated in PBS (pH 7.4). Five ml fractions were collected over theentire elution chromatography and absorbence at 280 and 215 nM weremonitored; the pass through and wash pools were also saved and analyzed.The FLAG®-polypeptide elution peak fractions were analyzed for thetarget protein via SDS-PAGE Silver staining and Western Blotting withthe anti-FLAG HRP conjugated antibody. The polypeptide elution fractionsof interest were pooled and concentrated from 80 ml to 12 ml using a10,000 Dalton molecular weight cutoff membrane spin concentrator(Millipore, Bedford, Mass.) according to the manufacturer'sinstructions.

To separate zalpha11 CFLG from other co-purifying proteins, thepolypeptide elution pooled fractions were subjected to a POROS HQ-50(strong anion exchange resin from PerSeptive BioSystems, Framingham,Mass.) at pH 8.0. A 1.0×6.0 cm column was poured and flow packed on aBioCad Sprint. The column was counter ion charged then equilibrated in20 mM TRIS pH 8.0 (Tris (Hydroxymethyl Aminomethane)). The sample wasdiluted 1:13 (to reduce the ionic strength of PBS) then loaded on thePoros HQ-50 column at 5 ml/minute. The column was washed for 10 columnvolumes (CVs) with 20 mM Tris pH 8.0 then eluted with a 40 CV gradientof 20 mM Tris/1 M sodium chloride (NaCl) at 10 ml/minute. 1.5 mlfractions were collected over the entire chromatography and absorbanceat 280 and 215 nM were monitored. The elution peak fractions wereanalyzed via SDS-PAGE Silver staining. Fractions of interest were pooledand concentrated to 1.5-2 ml using a 10,000 Dalton molecular weightcutoff membrane spin concentrator (Millipore, Bedford, Mass.) accordingto the manufacturer's instructions.

To separate zalpha11CFLG polypeptide from free FLAG® peptide and anycontaminating co-purifying proteins, the pooled concentrated fractionswere subjected to chromatography on a 1.5×90 cm Sephacryl S200(Pharmacia, Piscataway, N.J.) column equilibrated and loaded in PBS at aflow rate of 1.0 ml/min using a BioCad Sprint. 1.5 ml fractions werecollected across the entire chromatography and the absorbance at 280 and215 nM were monitored. The peak fractions were characterized viaSDS-PAGE Silver staining, and only the most pure fractions were pooled.This material represented purified zalpha11CFLG polypeptide.

This purified material was finally subjected to a 4 ml ActiClean Etox(Sterogene) column to remove any remaining endotoxins. The sample waspassed over the PBS equilibrated gravity column four times then thecolumn was washed with a single 3 ml volume of PBS, which was pooledwith the “cleaned” sample. The material was then 0.2 micron sterilefiltered and stored at −80° C. until it was aliquoted.

On Western blotted, Coomassie Blue and Silver stained SDS-PAGE gels, thezalpha11CFLG polypeptide was one major band of an apparent molecularweight of 50,000 Daltons. The mobility of this band was the same onreducing and non-reducing gels.

The protein concentration of the purified material was performed by BCAanalysis (Pierce, Rockford, Ill.) and the protein was aliquoted, andstored at −80° C. according to our standard procedures. On IEF(isoelectric focusing) gels the protein runs with a PI of less than 4.5.The concentration of zalpha11 CFLG polypeptide was 1.2 mg/ml.

C. Purification of Zalpha11-Fc4 Polypeptide from Transfected BHK 570Cells

Unless otherwise noted, all operations were carried out at 4° C. Thefollowing procedure was used for purifying zalpha11 polypeptidecontaining C-terminal fusion to human IgG/Fc (zalpha11-Fc4; Examples 4and 5). 12,000 ml of conditioned media from BHK 570 cells transfectedwith zalpha11-Fc4 (Example 5) was filtered through a 0.2 mm sterilizingfilter and then supplemented with a solution of protease inhibitors, tofinal concentrations of 0.001 mM leupeptin (Boerhinger-Mannheim,Indianapolis, Ind.), 0.001 mM pepstatin (Boerhinger-Mannheim) and 0.4 mMPefabloc (Boerhinger-Mannheim). A protein G sepharose (6 ml bed volume,Pharmacia Biotech) was packed and washed with 500 ml PBS (Gibco/BRL) Thesupplemented conditioned media was passed over the column with a flowrate of 10 ml/minute, followed by washing with 1000 ml PBS (BRL/Gibco).zalpha11-Fc4 was eluted from the column with 0.1 M Glycine pH 3.5 and 2ml fractions were collected directly into 0.2 ml 2 M Tris pH 8.0, toadjust the final pH to 7.0 in the fractions.

The eluted fractions were characterized by SDS-PAGE and western blottingwith anti-human Fc (Amersham) antibodies. Western blot analysis ofreducing SDS-PAGE gels reveal an immunoreactive protein of 80,000 KDa infractions 2-10. Silver stained SDS-PAGE gels also revealed an 80,000 KDazalpha11:Fc polypeptide in fractions 2-10. Fractions 2-10 were pooled.

The protein concentration of the pooled fractions was performed by BCAanalysis (Pierce, Rockford, Ill.) and the material was aliquoted, andstored at −80° C. according to our standard procedures. Theconcentration of the pooled fractions was 0.26 mg/ml.

Example 7 Assay Using Zalpha11 Soluble Receptor Zalpha11CEE,Zalpha11CFLG and Zalpha11-Fc4 Soluble Receptors in CompetitiveInhibition Assay

BaF3/Zalpha11 cells were spun down and washed in mIL-3 free media. Thecells were spun and washed 3 times to ensure the removal of the mIL-3.Cells were then counted in a hemacytometer. Cells were plated in a96-well format at 5000 cells per well in a volume of 100 μl per wellusing the mIL-3 free media.

Both media from the monkey spleen cell activation and the CD3+ selectedcells, described in Example 3, were added in separate experiments at50%, 25%, 12.5%, 6.25%, 3.125%, 1.5%, 0.75% and 0.375% concentrations,with or without zalpha11 soluble receptors (CEE, C-flag, and Fc4constructs; See, Example 6) at 10 μg/ml. The total assay volume was 200μl.

The assay plates were incubated 37° C., 5% CO₂ for 3 days at which timeAlamar Blue (Accumed) was added at 20 μl/well. Plates were againincubated at 37° C., 5% CO₂ for 24 hours. Plates were read on the Fmax™plate reader (Molecular Devices) as described above (Example 2). Resultsdemonstrated complete inhibition of cell growth from each of thedifferent zalpha11 soluble receptor constructs at 10 μg/ml, confirmingthat the factor in each sample was specific for the zalpha11 receptor.

Titration curves, diluting out the soluble receptors, were also runusing the above stated assay. Both the zalpha11CEE and zalpha11CFLGsoluble zalpha11 receptors were able to completely inhibit growth as lowas 20 ng/ml. The zalpha11-Fc4 soluble zalpha11 receptor was only aseffective at 1.5 μg/ml.

Example 8 Expression of Human Zalpha11 Soluble Receptor in E. coli

A. Construction of Expression Vector pCZR225 that ExpressesHuzalpha11/MBP-6H Fusion Polypeptide

An expression plasmid containing a polynucleotide encoding a humanzalpha11 soluble receptor fused C-terminally to maltose binding protein(MBP) was constructed via homologous recombination. The polynucleotidesequence for the MBP-zalpha11 soluble receptor fusion polypeptide isshown in SEQ ID NO:29, with the corresponding protein sequence shown inSEQ ID NO:30. The fusion polypeptide, designated huzalpha11/MBP-6H, inExample 9, contains an MBP portion (amino acid 1 (Met) to amino acid 388(Ser) of SEQ ID NO:30) fused to the human zalpha11 soluble receptor(amino acid 389 (Cys) to amino acid 606 (His) of SEQ ID NO:30). Afragment of human zalpha11 cDNA (SEQ ID NO:31) was isolated using PCR.Two primers were used in the production of the human zalpha11 fragmentin a PCR reaction: (1) Primer ZC20,187 (SEQ ID NO:32), containing 40 bpof the vector flanking sequence and 25 bp corresponding to the aminoterminus of the human zalpha11, and (2) primer ZC20,185 (SEQ ID NO:33),containing 40 bp of the 3′ end corresponding to the flanking vectorsequence and 25 bp corresponding to the carboxyl terminus of the humanzalpha11. The PCR Reaction conditions were as follows: 25 cycles of 94°C. for 30 seconds, 50° C. for 30 seconds, and 72° C. for 1 minute;followed by 4° C. soak, run in duplicate. Two μl of the 100 μl PCRreaction was run on a 1.0% agarose gel with 1×TBE buffer for analysis,and the expected approximately 660 bp fragment was seen. The remaining90 μl of PCR reaction was combined with the second PCR tube precipitatedwith 400 μl of absolute ethanol. The precipitated DNA used forrecombining into the SmaI cut recipient vector pTAP98 to produce theconstruct encoding the MBP-zalpha11 fusion, as described below.

Plasmid pTAP98 was derived from the plasmids pRS316 and pMAL-c2. Theplasmid pRS316 is a Saccharomyces cerevisiae shuttle vector (Hieter P.and Sikorski, R., Genetics 122:19-27, 1989). pMAL-C2 (NEB) is an E. coliexpression plasmid. It carries the tac promoter driving MalE (geneencoding MBP) followed by a His tag, a thrombin cleavage site, a cloningsite, and the rrnB terminator. The vector pTAP98 was constructed usingyeast homologous recombination. 100 ng of EcoR1 cut pMAL-c2 wasrecombined with 1 μg Pvul cut pRS316, 1 μg linker, and 1 μg Sca1/EcoR1cut pRS316. The linker consisted of oligos ZC19,372 (SEQ ID NO:34) (100pmol): ZC19,351 (SEQ ID NO:35) (1 pmol): ZC19,352 (SEQ ID NO:36) (1pmol), and ZC19,371 (SEQ ID NO:37) (100 pmol) combined in a PCRreaction. PCR reaction conditions were as follows: 10 cycles of 94° C.for 30 seconds, 50° C. for 30 seconds, and 72° C. for 30 seconds;followed by 4° C. soak. PCR products were concentrated via 100% ethanolprecipitation.

One hundred microliters of competent yeast cells (S. cerevisiae) werecombined with 10 μl of a mixture containing approximately 1 μg of thehuman zalpha11 receptor PCR product above, and 100 ng of SmaI digestedpTAP98 vector, and transferred to a 0.2 cm electroporation cuvette. Theyeast/DNA mixture was electropulsed at 0.75 kV (5 kV/cm), infinite ohms,25 μF. To each cuvette was added 600 μl of 1.2 M sorbitol and the yeastwas then plated in two 300 μl aliquots onto two-URA D plates andincubated at 30° C.

After about 48 hours, the Ura+ yeast transformants from a single platewere resuspended in 1 ml H₂O and spun briefly to pellet the yeast cells.The cell pellet was resuspended in 1 ml of lysis buffer (2% TritonX-100, 1% SDS, 100 mM NaCl, 10 mM Tris, pH 8.0, 1 mM EDTA). Five hundredmicroliters of the lysis mixture was added to an Eppendorf tubecontaining 300 μl acid washed glass beads and 200 μl phenol-chloroform,vortexed for 1 minute intervals two or three times, followed by a 5minute spin in a Eppendorf centrifuge at maximum speed. Three hundredmicroliters of the aqueous phase was transferred to a fresh tube, andthe DNA precipitated with 600 μl ethanol (EtOH), followed bycentrifugation for 10 minutes at 4° C. The DNA pellet was resuspended in100 μl H₂O.

Transformation of electrocompetent E. coli cells (MC1061, Casadaban et.al. J. Mol. Biol. 138, 179-207) was done with 1 μl yeast DNA prep and 40μl of MC1061 cells. The cells were electropulsed at 2.0 kV, 25 μF and400 ohms. Following electroporation, 0.6 ml SOC (2% Bacto™ Tryptone(Difco, Detroit, Mich.), 0.5% yeast extract (Difco), 10 mM NaCl, 2.5 mMKCl, 10 mM MgCl2, 10 mM MgSO4, 20 mM glucose) was plated in one aliquoton MM/CA+AMP 100 mg/L plates (Pryor and Leiting, Protein Expression andPruification 10:309-319, 1997).

Cells harboring the correct expression construct for human zalpha11receptor were identified by expression. Cells were grown in MM/CA with100 μg/ml Ampicillin for two hours, shaking, at 37° C. 1 ml of theculture was induced with 1 mM IPTG. 2-4 hours later the 250 μl of eachculture was mixed with 250 μl acid washed glass beads and 250 μl Thornerbuffer with 5% βME and dye (8 M urea, 100 mM Tris pH 7.0, 10% glycerol,2 mM EDTA, 5% SDS). Samples were vortexed for one minute and heated to65° C. for 10 minutes. 20 μl were loaded per lane on a 4%-12% PAGE gel(NOVEX). Gels were run in 1×MES buffer. The positive clones weredesignated pCZR225 and subjected to sequence analysis. Thepolynucleotide sequence of MBP-zalpha11 fusion is shown in SEQ ID NO:50.

B. Bacterial Expression of Human Huzalpha11/MBP-6H Fusion Polypeptide

One microliter of sequencing DNA was used to transform strain BL21. Thecells were electropulsed at 2.0 kV, 25 μF and 400 ohms. Followingelectroporation, 0.6 ml MM/CA with 100 mg/L Ampicillin.

Cells were grown in MM/CA with 100 μg/ml Ampicillin for two hours,shaking, at 37° C. 1 ml of the culture was induced with 1 mM IPTG. 2-4hours later the 250 μl of each culture was mixed with 250 μl acid washedglass beads and 250 μl Thorner buffer with 5% βME and dye (8 M urea, 100mM Tris pH 7.0, 10% glycerol, 2 mM EDTA, 5% SDS). Samples were vortexedfor one minute and heated to 65° C. for 10 minutes. 20 μl were loadedper lane on a 4%-12% PAGE gel (NOVEX). Gels were run in 1×MES buffer.The positive clones were used to grow up for protein purification of thehuzalpha11/MBP-6H fusion protein (Example 9, below).

Example 9 Purification of Huzalpha11/MBP-6H Soluble Receptor from E.coli Fermentation

Unless otherwise noted, all operations were carried out at 4° C. Thefollowing procedure was used for purifying huzalpha11/MBP-6H solublereceptor polypeptide. E. Coli cells containing the pCZR225 construct andexpressing huzalpha11/MBP-6H soluble receptor (Example 8) were grown upin SuperBroth II (12 g/L Casien, 24 g/L Yeast Extract, 11.4 g/Ldi-potassium phosphate, 1.7 g/L Mono-potassium phosphate; BectonDickenson, Cockeysville, Md.), and frozen in 0.5% glycerol. Twenty gramsof the frozen cells in SuperBroth II+Glycerol were used to purify theprotein. The frozen cells were thawed and diluted 1:10 in a proteaseinhibitor solution (Extraction buffer) prior to lysing the cells andreleasing the huzalpha11/MBP-6H soluble receptor protein. The dilutedcells contained final concentrations of 20 mM Tris (JT Baker,Philipsburg, N.J.) 100 mM Sodium Chloride (NaCl, Mallinkrodt, Paris,Ky.), 0.5 mM phenylmethylsulfonyl fluoride (PMSF, Sigma Chemical Co.,St. Louis, Mo.), 2 μg/ml Leupeptin (Fluka, Switzerland), and 2 μg/mlAprotinin (Sigma). A French Press cell breaking system (Constant SystemsLtd., Warwick, UK) with temperature of −7 to −10° C. and 30K PSI wasused to lyse the cells. The diluted cells were checked for breakage byA₆₀₀ readings before and after the French Press. The lysed cells werecentrifuged @18,000 G for 45 minutes to remove the broken cell debris,and the supernatant used to purify the protein. Total target proteinconcentrations of the supernatant was determined via BCA Protein Assay(Pierce, Rockford, Ill.), according to manufacturer's instructions.

A 25 ml column of Talon Metal Affinity resin (Clontech, Palo Alto,Calif.) (prepared as described below) was poured in a Bio-Rad, 2.5 cmD×10 cm H glass column. The column was packed and equilibrated bygravity with 10 column volumes (CVs) of Talon Equilibration buffer (20mM Tris, 100 mM NaCl, pH 8.0). The supernatant was batch loaded to Talonmetal affinity resin and was rocked overnight. The resin was poured backinto the column and was washed with 10 CV's of Talon Equilibrationbuffer by gravity, then gravity eluted with 140 ml of Elution buffer(Talon Equilibration buffer+200 mM Imidazole-Fluka Chemical). The taloncolumn was cleaned with 5 CVs of 20 mM 2-(N-Morpholino) ethanesulfonicacid pH 5.0 (MES, Sigma), 5 CVs of distilled H₂O, then stored in 20%Ethanol/0.1% Sodium Azide. Fourteen ml fractions were collected over theentire elution chromatography and the fractions were read withabsorbance at 280 and 320 nM and BCA protein assay; the pass through andwash pools were also saved and analyzed. The protein elution fractionsof interest were pooled and loaded straight to Amylose resin (NewEngland Biolabs, Beverly, Mass.).

To obtain more pure huzalpha11/MBP-6H polypeptide, the talon affinityelution pooled fractions were subjected to Amylose resin (22 mls) at pH7.4. A 2.5 cm D×10 cm H Bio-Rad column was poured, packed andequilibrated in 10 CVs of Amylose equilibration buffer−20 mM Tris (JTBaker), 100 mM NaCl (Mallinkrodt), 1 mM PMSF (Sigma), 10 mMbeta-Mercaptoethanol (BME, ICN Biomedicals Inc., Aurora, Ohio) pH 7.4.The sample was loaded by gravity flow rate of 0.5 ml/min. The column waswashed for 10 CVs with Amylose equilibration buffer, then eluted with ˜2CV of Amylose equilibration buffer+10 mM Maltose (Fluka Biochemical,Switzerland) by gravity. 5 ml fractions were collected over the entirechromatography and absorbance at 280 and 320 nM were read. The Amylosecolumn was regenerated with 1 CV of distilled H₂O, 5 CVs of 0.1% (w/v)SDS (Sigma), 5 CVs of distilled H₂O, and then 5 CVs of Amyloseequilibration buffer.

Fractions of interest were pooled and dialyzed in a Slide-A-Lyzer(Pierce) with 4×4 L PBS pH 7.4 (Sigma) to remove low molecular weightcontaminants, buffer exchange and desalt. After the changes of PBS, thematerial harvested represented the purified huzalpha11/MBP-6Hpolypeptide. The purified huzalpha11/MBP-6H polypeptide was analyzed viaSDS-PAGE Coomassie staining and Western blot analysis with theanti-rabbit HRP conjugated antibody (Rockland, Gilbertsville, Pa.). Theconcentration of the huzalpha11/MBP-6H polypeptide was 1.92 mg/ml asdetermined by BCA analysis.

Purified huzalpha11/MBP-6H polypeptide was prepared for injection intorabbits and sent to R & R Research and Development (Stanwood, Wash.) forantibody production. Rabbits were injected to produce antianti-huzalpha11/MBP-6H serum (Example 10, below).

Example 10 Zalpha11 Soluble Receptor Polyclonal Antibodies

Polyclonal antibodies were prepared by immunizing two female New Zealandwhite rabbits with the purified huzalpha11/MBP-6H polypeptide (Example9), or the purified recombinant zalpha11CEE soluble receptor (Example6A). Corresponding polyclonal antibodies were designated rabbitanti-huzalpha11/MBP-6H and rabbit anti-huzalpha11-CEE-BHK respectively.The rabbits were each given an initial intraperitoneal (IP) injection of200 mg of purified protein in Complete Freund's Adjuvant (Pierce,Rockford, Ill.) followed by booster IP injections of 100 mg purifiedprotein in Incomplete Freund's Adjuvant every three weeks. Seven to tendays after the administration of the third booster injection, theanimals were bled and the serum was collected. The rabbits were thenboosted and bled every three weeks.

The zalpha11-specific polyclonal antibodies were affinity purified fromthe rabbit serum using an CNBr-SEPHAROSE 4B protein column (PharmaciaLKB) that was prepared using 10 mg of the purified huzalpha11/MBP-6Hpolypeptide (Example 9) per gram CNBr-SEPHAROSE, followed by 20×dialysis in PBS overnight. Zalpha11-specific antibodies werecharacterized by an ELISA titer check using 1 mg/ml of the appropriateprotein antigen as an antibody target. The lower limit of detection(LLD) of the rabbit anti-huzalpha11/MBP-6H affinity purified antibody isa dilution of 500 pg/ml. The LLD of the rabbit anti-huzalpha11-CEE-BHKaffinity purified antibody is a dilution of 50 pg/ml.

Example 11 Identification of Cells Expressing Zalpha11 Receptor UsingRT-PCR

Specific human cell types were isolated and screened for zalpha11expression by RT-PCR. B-cells were isolated from fresh human tonsils bymechanical disruption through 100 μm nylon cell strainers (Falcon™;Bectin Dickenson, Franklin Lakes, N.J.). The B-cell suspensions wereenriched for CD19+ B-cells by positive selection with VarioMACS VS+magnetic column and CD19 microbeads (Miltenyi Biotec, Auburn, Calif.) asper manufacturer's instructions. T-cells and monocytes were isolatedfrom human apheresed blood samples. CD3+ T-cells were purified by CD3microbead VarioMACS positive selection and monocytes were purified byVarioMACS negative selection columns (Miltenyi) as per manufacturer'sinstructions. Samples from each population were stained and analyzed byfluorescent antibody cell sorting (FACS) (Bectin Dickinson, San Jose,Calif.) analysis to determine the percent enrichment and resultingyields. CD19+ B-cells were approximately 96%, purified CD3+ T-cells wereapproximately 95% purified, and monocytes were approximately 96%purified.

RNA was prepared, using a standard method in the art, from all threecell types that were either resting or activated. RNA was isolated fromresting cells directly from the column preparations above. The CD19+ andCD3+ cells were activated by culturing at 500,000 cells/ml in RPMI+10%FBS containing PMA 5 ng/ml (Calbiochem, La Jolla, Calif.) and Ionomycin0.5 ug/ml (Calbiochem) for 4 and 24 hours. The monocytes were activatedby culturing in RPMI+10% FBS containing LPS 10 ng/ml (Sigma St. LouisMo.) and rh1FN-γ 10 ng/ml (R&D, Minneapolis, Minn.) for 24 hours. Cellswere harvested and washed in PBS. RNA was prepared from the cell pelletsusing RNeasy Midiprep™ Kit (Qiagen, Valencia, Calif.) as permanufacturer's instructions and first strand cDNA synthesis wasgenerated with Superscript II™ Kit (GIBCO BRL, Grand Island, N.Y.) asper manufacturer's protocol.

Oligos ZC19907 (SEQ ID NO:38) and ZC19908 (SEQ ID NO:39) were used in aPCR reaction to screen the above described samples for a 1.2 kb fragmentcorresponding to zalpha11 message. PCR amplification was performed withTaq Polymerase (BRL Grand Island N.Y.), and conditions as follows: 35cycles of 95° C. for 1 min., 60° C. for 1 min., 72° C. for 30 sec.; 1cycle at 72° C. for 10 min.; and 4° C. soak. 10 ul of each 50 μlreaction volume was run on a 2% agarose 1XTAE gel to identify resultantproducts. PCR products were scored as (−) for no product, (+) for bandvisible, (++) increased presence of band and (+++) being the mostpredominant band, with results shown in Table 5 below.

TABLE 5 cDNA Source Activation PCR Product CD19+ cells  0 hr resting + 4 hr activated ++ 24 hr activated +++ CD3+ cells  0 hr resting −  4 hractivated ++ 24 hr activated − monocytes  0 hr resting − 24 hr activated−

These results indicated that zalpha11 message is present in restinghuman CD19+ B-cells and increases with mitogenic activation. It alsoappears to be expressed by human CD3+ T-cells only after 4 houractivation. There was no apparent message in either resting or activatedhuman monocytes.

Example 12 Zalpha11 Immunohistochemistry

A. Cell and Tissue Preparations

Positive controls consisted of BaF3 cells transfected with zalpha11receptor (Example 2) and lymphoid tissues known to express zalpha11receptor including mouse lymph node, spleen and thymus received from HSD(Harlan Sprague Dawley, Indianapolis, Ind.), monkey lymph node andspleen received from Regional Primate Research Center (University ofWashington, Seattle, Wash.), human lymph node and spleen received fromCHTN (Cleveland, Ohio). Negative controls performed on each sampleincluded: (1) untransfected BaF3 cells, (2) liver and brain tissue frommouse and human known not to express zalpha11 receptor, (3) stainingwith antibody dilution buffer (Ventann Bioteck Systems, Tucson Ariz.) inthe absence of primary antibody, and (4) using zalpha11 soluble receptorprotein in competition experiments.

Other cell samples were examined. Both non-stimulated and stimulatedHL60 cells were assayed. HL60 cells are a promyelocytic cell line, whichcan be differentiated into myeloid or granulocyte lineages withdifferent reagents. Stimulated HL60 samples were prepared as follows:(1) HL60 cells were treated with 10 ng/ml of phorbol-myristate-acetate(PMA) (Sigma, St. Louis, Mo.) for 48 hours to differentiate intomonocyte lineage cells; and (2) HL60 cells treated with 1.25% DMSO(Sigma) for 4 days to differentiate into neutrophil-like cells. Inaddition, human polymorphonuclear (PMN) cells, human granulocytes, humanperipheral blood lymphocytes (PBL) and human monocytes from fresh humanblood were examined (prepared in house using routine methods in theart). The cells and tissues described above were fixed overnight in 10%NBF (Surgipath, Richmond, Ill.), and embedded in paraplast X-tra (OxfordScientific, St. Louis, Mo.), and sectioned at 5 μm with a Reichart-Jung2050 microme (Leica Instruments GmbH, Nussloch, Germany).

B. Immunohistochemistry

Tissue slides were deparaffinized, hydrated to buffer (water), andsubjected to steam HIER treatment in Antigen Retrieval Citra buffer(BioGenex, San Roman, Calif.) for 20 minutes. 5% normal goat serum(Vector, Burlingame, Calif.) was used to block non-specific binding for10 minutes. Immunocytochemical screening analyses were performed usingpolyclonal antibodies to zalpha11 soluble receptor protein (rabbitanti-huzalpha11-MBP-6H and rabbit anti-huzalpha11-CEE-BHK; Example 10)as the primary antibodies, at dilutions of 1:200 and 1:400 respectively.Biotin conjugated goat anti-rabbit IgG (Vector; Cat. No. BA-1000, 1.5mg/ml) was used as the secondary antibody at dilution of 1:200. Inseparate samples, protein competition was performed by using additionalzalpha11 CEE soluble receptor protein (in 10× fold excess) (Example 6A)to the primary antibody to pre-block primary antibody immunoreaction.This competition was used as a control for the rabbit polyclonalantibody specificity to zalpha11. Detection was performed on the VentanaChemMate 500 instrument using a ChemMate DAB Kit (labeledStreptavidin-Biotin Kit with application of a streptavidin-horseradishperoxidase conjugate, and DAB substrate) according to manufacturer'sinstruction and using the manufacturer's hematoxylin counterstain for 30seconds (Ventana Biotek Systems, Tucson, Ariz.).

High expression of zalpha11 was observed in the PMA-activated HL60cells. Low level expression was observed in PBL and HL60 cells withoutstimulation. A subset of cells in the spleen, thymus and lymph node ofmouse showed positive staining. Lymph node and spleen of both human andmonkey, and HL60 cells with DMSO stimulation showed minimal or nostaining. The signal seen in the cells and tissues was mostly competedout by using the excess zalpha11 soluble receptor protein. The negativecontrol tissues of brain and liver showed no staining.

Example 13 Identifying Peripheral Blood Mononuclear Cells (PBMNC's) thatExpress Zalpha11 Receptor Using Polyclonal Rabbit Anti-Sera to Zalpha11Soluble Receptor

200 ml fresh heparinized blood was obtained from a normal donor. Bloodwas diluted 1:1 in PBS, and separated using a Ficoll-Paque PLUS gradient(Pharmacia Biotech, Uppsala, Sweden), and the lymphocyte interfacecollected. Cells were washed 2× in PBS and resuspended in RPMI+5% FBSmedia at a concentration of 2×10⁶ cells/ml.

In order to determine whether expression of zalpha11 receptor isaffected by the activation state of the lymphocyte cells, i.e., betweenresting and activated cells several stimulation conditions were used: 1)unstimulated, i.e., media alone (RPMI+5% FBS media); 2) stimulated withPMA 10 ng/ml+Ionomycin 0.5 μg/ml (both from Calbiochem); and 3) PHAactivation (phytohemagglutinin-P, Difco/VWR). The cells were incubatedat 37° C. for 17 hours then collected for staining to detect expressionof zalpha11 receptor.

An indirect staining protocol was used. Briefly, the human lymphocytecells were suspended in staining buffer (PBS+0.02% NaN3+BSA 1% normalhuman serum 2%) and plated at 2×10⁵ cells in 50 μl/well in a 96 wellplate. Antibodies to the zalpha11CEE soluble receptor (Example 15) wereused to determine whether they co-stained with a B-cell (CD19), T-cell(CD3) or monocyte marker (CD14) on the isolated human lymphocytes. Arabbit polyclonal sera to zalpha11 soluble receptor (Rbanti-huzalpha11-CEE-BHK) (Example 10) at 10 μg/ml was used as theantibody to identify zalpha11 on the lymphocytes. A secondary antibody,goat anti-rabbit Ig-FITC (Biosource, Camarillo, Calif.), was used tovisualize the Rb anti-huzalpha11-CEE-BHK antibody binding to thezalpha11 receptors. Other antibodies were simultaneously used to stain Tcells (CD3-PE; PharMingen, San Diego, Calif.), B cells (CD19-PE)(PharMingen), and monocytes (CD14-PE) (PharMingen) in order to identifyco-staining of the anti-zalpha11 receptor antibody on these cell types.Various controls were used to determine non-specific binding andbackground levels of staining: (1) an irrelevant rabbit polyclonal serawas used as a non-specific control; and (2) secondary antibody alone wasused to determine background binding of that reagent. Purified,zalpha11CEE soluble receptor (Example 6) was used in about a 10-foldexcess as a competitive inhibitor to verify the specificity of therabbit anti-huzalpha11-CEE-BHK antibody to zalpha11 soluble receptor.

After plating the cells and adding the primary and co-stainingantibodies, the cells were incubated on ice for 30 minutes, washed 2×with staining buffer, and stained with the secondary antibody, goatanti-rabbit Ig-FITC (Biosource), for 30 minutes on ice. Cells werewashed 2× staining buffer, and resuspended at 200 μl per well instaining buffer containing the viability stain 7AAD at about 1 μg/mlfinal concentration (Sigma, St. Louis, Mo.). Samples were read on theFACS-Caliber (Becton-Dickinson, San Jose, Calif.) and viable cellsanalyzed.

The rabbit polyclonal to zalpha11 receptor stained resting B cells. Thesignal on resting B cells was brighter than the signal achieved usingthe irrelevant rabbit sera, and the signal was diminished to a greaterextent on B cells than on T cells with the addition of excesszalpha11-CEE soluble receptor. This experiment was repeated usingseparated B and T cells, and the results were very similar. Again thestaining with the polyclonal rabbit anti-huzalpha11-CEE-BHK antibody tozalpha11 receptor was highest on resting B cells.

Example 14 Zalpha11 Receptor Expression in Various Tissues UsingReal-Time Quantitative RT/PCR

A. Primers and Probes for Quantitative RT-PCR

Real-time quantitative RT-PCR using the ABI PRISM 7700 SequenceDetection System (PE Applied Biosystems, Inc., Foster City, Calif.) hasbeen previously described (See, Heid, C. A. et al., Genome Research6:986-994, 1996; Gibson, U. E. M. et al., Genome Research 6:995-1001,1996; Sundaresan, S. et al., Endocrinology 139:4756-4764, 1998. Thismethod incorporates use of a gene specific probe containing bothreporter and quencher fluorescent dyes. When the probe is intact thereporter dye emission is negated due to the close proximity of thequencher dye. During PCR extension using additional gene-specificforward and reverse primers, the probe is cleaved by 5′ nucleaseactivity of Taq polymerase which releases the reporter dye from theprobe resulting in an increase in fluorescent emission.

The primers and probes used for real-time quantitative RT-PCR analysesof zalpha11 receptor expression were designed using the primer designsoftware Primer Express™ (PE Applied Biosystems, Foster City, Calif.).Primers for human zalpha11 receptor were designed spanning anintron-exon junction to eliminate amplification of genomic DNA. Theforward primer, ZC22,277 (SEQ ID NO:40) and the reverse primer, ZC22,276(SEQ ID NO:41) were used in a PCR reaction (below) at about 300 nMconcentration to synthesize a 143 bp product. The corresponding zalpha11TaqMan® probe, designated ZG31 (SEQ ID NO:42) was synthesized andlabeled by PE Applied Biosystems. The ZG31 probe was labeled at the 5′end with a reporter fluorescent dye (6-carboxy-fluorescein) (FAM) (PEApplied Biosystems) and at the 3′ end with a quencher fluorescent dye(6-carboxy-tetramethyl-rhodamine) (TAMRA) (PE Applied Biosystems).

As a control to test the integrity and quality of RNA samples tested,all RNA samples (below) were screened for rRNA using a primer and probeset ordered from PE Applied Biosystems (cat No. 4304483). The kitcontains an rRNA forward primer (SEQ ID NO:43) and the rRNA reverseprimer (SEQ ID NO:44), rRNA TaqMan® probe (SEQ ID NO:45) The rRNA probewas labeled at the 5′ end with a reporter fluorescent dye VIC (PEApplied Biosystems) and at the 3′ end with the quencher fluorescent dyeTAMRA (PE Applied Biosystems). The rRNA results also serve as aninternal control and allow for the normalization of the zalpha11 mRNAexpression results seen in the test samples.

RNA samples from human CD3, CD19 and monocyte cell types were preparedand described as per Example 11 above. Control RNA was prepared, usingRNeasy Miniprep™ Kit (Qiagen, Valencia, Calif.) as per manufacturer'sinstructions, from approximately 10 million BaF3 cells expressing humanzalpha11 receptor (Example 2A).

B. Real-Time Quantitative RT-PCR

Relative levels of zalpha11 mRNA were determined by analyzing total RNAsamples using the one-step RT-PCR method (PE Applied Biosystems). TotalRNA from BaF3 cells expressing human zalpha11 receptor was isolated bystandard methods and used to generate a standard curve used forquantitation. The curve consisted of 10-fold serial dilutions rangingfrom 2.5-2.5×10⁻⁴ ng/μl for the rRNA screen and 250-0.025 ng/μl for thezalpha11 screen with each standard curve point analyzed in triplicate.The total RNA samples from the cells were also analyzed in triplicatefor human zalpha11 receptor transcript levels and for levels of rRNA asan endogenous control. In a total volume of 25 μl, each RNA sample wassubjected to a One-Step RT-PCR reaction containing: approximately 25 ngof total RNA in buffer A (50 mM KCL, 10 mM Tris-HCL); the internalstandard dye, carboxy-x-rhodamine (ROX); appropriate primers(approximately 50 nM rRNA primers (SEQ ID NO:43 and SEQ ID NO:44) forthe rRNA samples; and approximately 300 nM ZC22,277 (SEQ ID NO:40) andZC22,276 (SEQ ID NO:41) primers for zalpha11 samples); the appropriateprobe (approximately 50 nM rRNA TaqMan® probe (SEQ ID NO:45) for rRNAsamples, approximately 100 nM ZG31 (SEQ ID NO:42) probe for zalpha11samples); 5.5 mM MgCl₂; 300 μM each d-CTP, d-ATP, and d-GTP and 600 μMof d-UTP; MuLV reverse transcriptase (0.25 U/μl); AmpliTaq™ Gold DNApolymerase (0.025 U/μl) (PE Applied Biosystems); and RNase Inhibitor(0.4 U/μl) (PE Applied Biosystems). PCR thermal cycling conditions wereas follows: an initial reverse transcription (RT) step of one cycle at48° C. for 30 minutes; followed by an AmpliTaq Gold™ (PE AppliedBiosystems) activation step of one cycle at 95° C. for 10 minutes;followed by 40 cycles of amplification at 95° C. for 15 seconds and 60°C. for 1 minute.

Relative zalpha11 RNA levels were determined by using the Standard CurveMethod as described by the manufacturer, PE Biosystems (User BulletinNo. 2: ABI Prism 7700 Sequence Detection System, Relative Quantitationof Gene Expression, Dec. 11, 1997). The rRNA measurements were used tonormalize the zalpha11 levels and the resting CD3+ RNA sample was usedas a calibrator. Resting CD3 was arbitrarily chosen as the calibratorand given a value of 1.00. The rest of the samples were comparedrelative to the calibrator. Data are shown in Table 6 below.

TABLE 6 Sample Resting 4 hr Stimulation 24 hr Stimulation CD3 1.00 15.2716.70 CD19 20.14 65.08 25.42 Monocytes 0.05 no data 0.26

There was a 15-fold increase in zalpha11 receptor expression in CD3+ at4 and 24 hrs. Resting CD19 had 20 fold increase in receptor expressionrelative to resting CD3+. There was a 3 fold increase with 4 hrstimulation that fell back to resting levels by 24 hrs. Monocytes showedno detectable zalpha11 receptor expression in this assay.

C. Purified Human T, NK, and B Cells as a Primary Source Used to AssessHuman Zalpha11 Receptor Expression

Whole blood (150 ml) was collected from a healthy human donor and mixed1:1 with PBS in 50 ml conical tubes. Thirty ml of diluted blood was thenunderlayed with 15 ml of Ficoll Paque Plus (Amersham Pharmacia Biotech,Uppsala, Sweden). These gradients were centrifuged 30 min at 500 g andallowed to stop without braking. The RBC-depleted cells at the interface(PBMC) were collected and washed 3 times with PBS. The isolated humanPBMC yield was 200×10c6 prior to selection described below.

The PBMCs were suspended in 1.5 ml MACS buffer (PBS, 0.5% EDTA, 2 mMEDTA) and 3×10e6 cells were set aside for control RNA and for flowcytometric analysis. The 0.25 ml anti-human CD8 microbeads (MiltenyiBiotec) were added and the mixture was incubated for 15 min at 4 degreesC. These cells labeled with CD8 beads were washed with 30 ml MACSbuffer, and then resuspended in 2 ml MACS buffer.

A VS+ column (Miltenyi) was prepared according to the manufacturer'sinstructions. The VS+ column was then placed in a VarioMACS magneticfield (Miltenyi). The column was equilibrated with 5 ml MACS buffer. Theisolated primary mouse cells were then applied to the column. The CD8negative cells were allowed to pass through. The column was rinsed with9 ml (3×3 ml) MACS buffer. The column was then removed from the magnetand placed over a 15 ml falcon tube. CD8+ cells were eluted by adding 5ml MACS buffer to the column and bound cells flushed out using theplunger provided by the manufacturer. The yield of CD8+ selected humanperipheral T cells was 51×10e6 total cells. The CD8-negative flowthrough cells were collected, counted, stained with anti-human CD4coated beads, then incubated and passed over a new VS+ column at thesame concentrations as described above. The yield of CD4+ selected humanperipheral T cells was 42×10c6 total cells.

A sample of each of the CD8+ and CD4+ selected human T cells was removedfor staining and sorting on a fluorescence activated cell sorter (FACS)to assess their purity. A PE-conjugated anti-human CD4 antibody, ananti-human CD8-FITC Ab, and an anti-human CD19-CyChrome Ab (all fromPharMingen) were used for staining the CD8+ and CD4+ selected cells. TheCD8-selected cells in this first experiment were 80% CD8+, and theCD4-selected cells were 85% CD4+. In 2 subsequent experiments (Example14B), the CD8+ purified cells were 84% and 81% pure, and the CD4+ cellswere 85% and 97% pure, respectively. In one experiment, we stained thenon-binding (flow-through) cells with anti-human CD19-coated beads(Miltenyi) and ran them over a third magnetic bead column to isolateCD19+ B cells (these were 92% pure).

The human CD8+, CD4+ and CD19+ selected cells were activated byincubating 0.5×10⁶ cells/ml in RPMI+5% human ultraserum (GeminiBioproducts, Calabasas, Calif.)+PMA 10 ng/ml and Ionomycin 0.5 μg/ml(Calbiochem) for 4, 16, or 24 hours at 37° C. The T-cells(2.5×10e6/well) were alternately stimulated in 24-well plates pre-coatedovernight with 0.5 μg/ml plate-bound anti-CD3 mAb UCHT1 (PharMingen)with or without soluble anti-CD28 mAb (PharMingen) at 5 μg/ml. At eachtimepoint, the cells were harvested, pelleted, washed once with PBS, andpelleted again. The supernatant was removed and the pellets weresnap-frozen in a dry ice/ethanol bath, then stored at −80° C. for RNApreparation at a later date.

In a separate experiment, human NK cells were enriched from FicolledPBMC by negative selection using the human NK enrichment system(consisting of antibodies to CD3, CD4, CD14, CD19, CD66b, andglycophorin A) from Stem Cell Technologies (Vancouver, B.C., Canada).Cell pellets were prepared from freshly isolated NK cells from 2different donors, or from NK cells cultured 24 hours in media only or inmedia supplemented with 20 ng/ml IL-15. RNA from a human NK cell linederived from a malignant non-Hodgkin's lymphoma and designated NK-92(ATCC No. CRL-2407) was also tested. As positive controls, RNA wasisolated from the human B cell lines CESS (ATCC No. TIB-190), IM-9 (ATCCNo. CCL-159), and HS-Sultan (CRL-1484).

Real Time-PCR was performed on these human NK, CD8+, CD4+ and CD19+selected cells as described above for assessing human zalpha11 receptorexpression. Relative levels of zalpha11 receptor RNA were determined byanalysis of total RNA samples using the One-Step RT-PCR method (PEApplied Biosystems). RNA from BaF3 cells expressing human zalpha11receptor was used to generate appropriate control for standard curvesfor the real-time PCR described in Example 14C above. Results of theexperiments analyzing the expression of the zalpha11 Ligand and zalphareceptor in stimulated and unstimulated cells are as described inExample 14D-E below.

D. Expression of Human Zalpha11 Receptor and Ligand in CD4+, CD8+ andCD19+ Cells

The first experiment used RT-PCR, described above, to assess zalpha11receptor expression in unstimulated and anti-CD3 stimulated CD4+ andCD8+ samples at timepoints of Oh (unstimulated (“resting”) cells), andat 4 h, 15.5 h and 24 h, after stimulation. The resting CD4+ sample wasarbitrarily chosen as the calibrator and given a value of 1.00. Therewas approximately a 4-fold increase in receptor expression inunstimulated CD4+ cells from 4 h to 24 h of culture and about an 8-foldincrease over the same time period in anti-CD3 stimulated CD4+ cells.The CD8+ cells showed a 7-fold increase in zalpha11 receptor expressionthat peaked at 4 hrs and decreased over time. With anti-CD3 stimulation,the CD8+ cells had a constant 8-fold increase in receptor expression.

The second experiment used RT-PCR to assess zalpha11 receptor expressionin anti-CD3-stimulated, PMA+Ionomycin-stimulated and unstimulated CD4+and CD8+ samples at timepoints of 0 h, and at 3.5 h, 16 h and 24 h afteractivation. The resting CD8+ sample was arbitrarily chosen as thecalibrator and given a value of 1.00. The resting CD4+ and CD8+ cellsdid not have significant amounts of receptor expression. The expressionwas about 3 fold higher in the PMA+Ionomycin-stimulated CD4+ samples at3.5 h, 16 h and 24 h after stimulation. The expression in anti-CD3activated CD4+ cells peaked at 10-fold above background levels at 3.5 hafter stimulation, then fell back to levels 4-fold above background at16 h after stimulation. The CD8+ cells showed a 4-fold expressionincrease at 3.5 h after PMA+Ionomycin stimulation, with expressiondecreasing at subsequent timepoints. As in the first experiment, theanti-CD3 stimulated CD8+ cells again exhibited an 8-fold abovebackground induction of receptor expression.

The final experiment used RT-PCR to assess zalpha11 receptor expressionin anti-CD3- and anti-CD3/anti-CD28-stimulated and unstimulated CD4+ andCD8+ samples at timepoints of 0 h, and at 2 h, 4 h, and 16 h afterstimulation. CD19+ cells activated with PMA+Ionomycin were also screenedfor receptor expression at the same time intervals. The resting CD4+sample was arbitrarily chosen as the calibrator and given a value of1.00. The 2 h anti-CD3 stimulated CD4+ cells only had a 4-fold inductionof receptor, compared to the 10-fold induction seen at 3.5 h in theprevious experiment. The combination of anti-CD3 and anti-CD28 increasedexpression to 8-fold above background. The 16 h anti-CD3/anti-CD28stimulated CD8+ cells had very low receptor expression levels, as seenin the CD8+ cells in previous experiments (above). The CD19+ cellsstimulated with PMA+Ionomycin had the most significant receptorexpression with a 19-fold increase at 2 h, but the expression levelsdecreased back to those of resting cells by 16 h.

A certain amount of variation was expected between blood draws (i.e.multiple samples at different times from the same patient and betweenmultiple patients). Therefore, data trends were analyzed within eachstudy or from a single blood sample and the three experiments above werecompared for an overall conclusion. The trend from the Real Time PCRexperiments described above is that of all the cell types tested, CD19+B cells activated with PMA+ionomycin expressed the highest levels ofzalpha11 receptor RNA. CD4+ and CD8+ cells can also be stimulated toexpress receptor, but at lower levels than in B cells.

E. Expression of Human Zalpha11 Receptor in Human NK Cells

Real Time PCR was also performed on human NK cells, purified asdescribed in Example 14C, above. The NK-92 sample was arbitrarily chosenas the calibrator and given a value of 1.00. There was approximately a4.5-fold increase in receptor expression in the positive control CESScells, a 1.5-fold increase in IM-9 cells, and no increase in theHS-Sultan cells (0.9-fold relative to NK-92). The NK cells, either freshor cultured overnight with or without IL-15, expressed very similarlevels of zalpha11 Receptor as NK-92 (with values ranging from0.9-1.2-fold different relative to NK-92).

Example 15 Identification of Cells Expressing Zalpha11 Receptor Using InSitu Hybridization

Specific human tissues were isolated and screened for zalpha11expression by in situ hybridization. Various human tissues prepared,sectioned and subjected to in situ hybridization included thymus,spleen, tonsil, lymph node and lung. The tissues were fixed in 10%buffered formalin and blocked in paraffin using standard techniques.Tissues were sectioned at 4 to 8 microns. Tissues were prepared using astandard protocol (“Development of non-isotopic in situ hybridization”at http://dir.niehs.nih.gov/dirlep/ish.html). Briefly, tissue sectionswere deparaffinized with HistoClear (National Diagnostics, Atlanta, Ga.)and then dehydrated with ethanol. Next they were digested withProteinase K (50 μg/ml) (Boehringer Diagnostics, Indianapolis, Ind.) at37° C. for 2 to 20 minutes. This step was followed by acetylation andre-hydration of the tissues.

Two in situ probes generated by PCR were designed against the humanzalpha11 sequence. Two sets of oligos were designed to generate probesfor separate regions of the zalpha11 CDNA: (1) Oligos ZC23,684 (SEQ IDNO:60) and ZC23,656 (SEQ ID NO:61) were used to generate a 413 bp probefor zalpha11; and (2) Oligos ZC23,685 (SEQ ID NO:62) and ZC23,657 (SEQID NO:63) were used to generate a 430 bp probe for zalpha11. The secondprobe is 1500 bp 3′ of the first zalpha11 probe. The antisense oligofrom each set also contained the working sequence for the T7 RNApolymerase promoter to allow for easy transcription of antisense RNAprobes from these PCR products. The PCR reaction conditions were asfollows: 30 cycles at 94° C. for 30 sec, 60° C. for 1 min., 72° C. for1.5 min. The PCR products were purified by Qiagen spin columns followedby phenol/chloroform extraction and ethanol precipitation. Probes weresubsequently labeled with digoxigenin (Boehringer) or biotin(Boehringer) using an In Vitro transcription System (Promega, Madison,Wis.) as per manufacturer's instruction.

In situ hybridization was performed with a digoxigenin- orbiotin-labeled zalpha11 probe (above). The probe was added to the slidesat a concentration of 1 to 5 pmol/ml for 12 to 16 hours at 55-60° C.Slides were subsequently washed in 2×SSC and 0.1×SSC at 50° C. Thesignals were amplified using tyramide signal amplification (TSA) (TSA,in situ indirect kit; NEN) and visualized with Vector Red substrate kit(Vector Lab) as per manufacturer's instructions. The slides were thencounter-stained with hematoxylin (Vector Laboratories, Burlingame,Calif.).

A signal was seen in the thymus, tonsil, lung, and lymph node. Thepositive-staining cells appeared to be lymphocytes.

Example 16 Secretion Trap Assay

A secretion trap assay was used to identify the cDNA for the zalpha11Ligand. The positive DNA pools obtained from the expression cloningeffort were described in commonly owned U.S. patent application Ser. No.09/522,217.

Conditioned medium from DNA clones transfected into BHK cells in 96-wellformat, were put into the proliferation assay using BaF3/zalpha11 cellsdescribed in Example 2. Several DNA pools gave positive activities thatwere repeated and neutralized with zalpha11 soluble receptors (Example6). One positive DNA pool was transfected into COS cells in 12-wellformat, using the Lipofectamine™ method described below.

A secretion trap assay was then performed using zalpha11 solublereceptors (C-terminal Glu-Glu tagged either with or withoutbiotinylation; C-terminal Flag tagged; or Fc4 zalpha11 soluble receptorfusions) (Example 6) to test the direct binding between the zalpha11Ligand in the positive pool and zalpha11 soluble receptors (see below).The result was positive, enabling the detection and isolation of clonesexpressing the zalpha11 Ligand. Plates were shaken at 37° C. for 24hours, and then DNA minipreps (QiaPrep™ 96 Turbo Miniprep Kit; Qiagen)were prepared in 96-well format using a TomTech Quadra 9600. The plasmidDNA was then pooled in the format of rows and columns, transfected intoCOS cells, and then the positive pools were determined by secretion trapas described below.

COS Cell Transfections

The COS cell transfection was performed as follows: Mix 3 ul pooled DNAand 5 ul Lipofectamine™ in 92 ul serum free DMEM media (55 mg sodiumpyruvate, 146 mg L-glutamine, 5 mg transferrin, 2.5 mg insulin, 1 μgselenium and 5 mg fetuin in 500 ml DMEM), incubate at room temperaturefor 30 minutes and then add 400 ul serum free DMEM media. Add this 500ul mixture onto 1.5×10⁵ COS cells/well plated on 12-well tissue cultureplate and incubate for 5 hours at 37° C. Add 500 ul 20% FBS DMEM media(100 ml FBS, 55 mg sodium pyruvate and 146 mg L-glutamine in 500 mlDMEM) and incubate overnight.

Secretion Trap Assay

The secretion trap was performed as follows: Media was rinsed off cellswith PBS and then fixed for 15 minutes with 1.8% Formaldehyde in PBS.Cells were then washed with TNT (0.1 M Tris-HCL, 0.15 M NaCl, and 0.05%Tween-20 in H₂O), and permeated with 0.1% Triton-X in PBS for 15minutes, and again washed with TNT. Cells were blocked for 1 hour withTNB (0.1 M Tris-HCL, 0.15 M NaCl and 0.5% Blocking Reagent (NENRenaissance TSA-Direct Kit) in H₂O), and washed again with TNT. If usingthe biotinylated protein, the cells were blocked for 15 minuteincubations with Avidin and then Biotin (Vector Labs), washingin-between with TNT. Depending on which soluble receptor was used, thecells were incubated for 1 hour with: (A) 1-3 μg/ml zalpha11 solublereceptor zalpha11-Fc4 fusion protein (Example 6); (B) 3 μg/ml zalpha11soluble receptor C-terminal FLAG tagged, zalpha11CFLG (Example 6); (C) 3μg/ml zalpha11 soluble receptor C-terminal GluGlu tagged, zalpha11CEE(Example 6); or (D) 3 μg/ml biotinylated zalpha11 soluble receptorzalpha11CEE (Example 6) in TNB. Cells were then washed with TNT.Depending on which soluble receptor was used, cells were incubated foranother hour with: (A) 1:200 diluted goat-anti-human Ig-HRP (Fcspecific); (B) 1:1000 diluted M2-HRP; (C) 1:1000 diluted anti-GluGluantibody-HRP; or (D) 1:300 diluted streptavidin-HRP (NEN kit) in TNB.Again cells were washed with TNT.

Positive binding was detected with fluorescein tyramide reagent diluted1:50 in dilution buffer (NEN kit) and incubated for 4-6 minutes, andwashed with TNT. Cells were preserved with Vectashield Mounting Media(Vector Labs Burlingame, Calif.) diluted 1:5 in TNT. Cells werevisualized using a FITC filter on fluorescent microscope.

Example 17 Mouse zalpha11 Ligand Binds to Human Zalpha11 SolubleReceptor in Secretion Trap Assay

A plasmid containing DNA encoding the mouse zalpha11 Ligand (SEQ IDNO:47) was transfected into COS cells, and the binding of human zalpha11soluble receptor zalpha11-Fc4 (Example 6C) to the transfected COS cellswas tested by a secretion trap assay (Example 16). The assay confirmedthat the mouse zalpha11 Ligand binds to human zalpha11 soluble receptor.

The COS cell transfection was performed as per Example 16 using 0.7 μgof the plasmid in 3 μl. The secretion trap was performed as as perExample 16 using 1 μg/ml zalpha11 soluble receptor Fc4 fusion protein(Example 6C) in TNB, and 1:200 diluted goat-anti-human Ig-HRP (Fcspecific) in TNB for the detectable antibody. Positive binding of thesoluble human zalpha11 receptor to the prepared fixed cells was detectedwith fluorescein tyramide reagent, preserved and visualized according toExample 16. The positive result indicated the mouse zalpha11 Ligandbinds to human zalpha11 soluble receptor.

Example 18 Mouse Zalpha11 Ligand Activates Human Zalpha11 Receptor inBaF3 Assay Using Alamar Blue

BaF3/Zalpha11 cells were spun down, washed and plated in mIL-3 freemedia as described in Example 2. Proliferation of the BaF3/Zalpha11cells was assessed using serum-free conditioned media from BHK cellsexpressing mouse zalpha11 Ligand (SEQ ID NO:47). Conditioned media wasdiluted with mIL-3 free media to: 50%, 25%, 12.5%, 6.25%, 3.125%, 1.5%,0.75% and 0.375% concentrations. The proliferation assay was performedas per Example 2. Results confirmed the proliferative response of theBaF3/Zalpha11 cells to mouse zalpha11 Ligand. The response, as measured,was approximately 5-fold over background at the 50% concentration.

Example 19 Zalpha11 Ligand Activates Human Zalpha11 Receptor inLuciferase Assay

A. Construction of BaF3/KZ134/Zalpha11 Cell Line

The KZ134 plasmid was constructed with complementary oligonucleotidesZC12,749 (SEQ ID NO:48) and ZC12,748 (SEQ ID NO:49) that contain STATtranscription factor binding elements from 4 genes. A modified c-fos Sisinducible element (m67SIE, or hSIE) (Sadowski, H. et al., Science261:1739-1744, 1993), the p21 SIE1 from the p21 WAF1 gene (Chin, Y. etal., Science 272:719-722, 1996), the mammary gland response element ofthe β-casein gene (Schmitt-Ney, M. et al., Mol. Cell. Biol.11:3745-3755, 1991), and a STAT inducible element of the Fcg RI gene,(Seidel, H. et al., Proc. Natl. Acad. Sci. 92:3041-3045, 1995). Theseoligonucleotides contain Asp718-XhoI compatible ends and were ligated,using standard methods, into a recipient firefly luciferase reportervector with a c-fos promoter (Poulsen, L. K. et al., J. Biol. Chem.273:6229-6232, 1998) digested with the same enzymes and containing aneomycin selectable marker. The KZ134 plasmid was used to stablytransfect BaF3 cells, using standard transfection and selection methods,to make the BaF3/KZ134 cell line.

A stable BaF3/KZ134 indicator cell line, expressing the full-lengthzalpha11 receptor was constructed as per Example 1, using about 30 μg ofthe zalpha11 expression vector. Clones were diluted, plated and selectedusing standard techniques. Clones were screened by luciferase assay (seeExample 19B, below) using the human zalpha11 Ligand conditioned media asan inducer. Clones with the highest luciferase response (via STATluciferase) and the lowest background were selected. A stabletransfectant cell line was selected. The cell line was calledBaF3/KZ134/zalpha11.

B. Human and Mouse Zalpha11 Ligand Activates Human Zalpha11 Receptor inBaF3/KZ134/Zalpha11 Luciferase Assay

BaF3/KZ134/Zalpha11 cells were spun down and washed in mIL-3 free media.The cells were spun and washed 3 times to ensure removal of mIL-3. Cellswere then counted in a hemacytometer. Cells were plated in a 96-wellformat at about 30,000 cells per well in a volume of 100 μl per wellusing the mIL-3 free media. The same procedure was used foruntransfected BaF3/KZ134 cells for use as a control in the subsequentassay.

STAT activation of the BaF3/KZ134/Zalpha11 cells was assessed usingconditioned media from (1) BHK570 cells transfected with an expressionvector encoding the human zalpha11 Ligand (SEQ ID NO:10) or (2) BHK570cells transfected with an expression vector encoding the mouse zalpha11Ligand (SEQ ID NO:47), or (3) mIL-3 free media to measure media-onlycontrol response. Conditioned media was diluted with RPMI mIL-3 freemedia to 50%, 25%, 12.5%, 6.25%, 3.125%, 1.5%, 0.75% and 0.375%concentrations. 100 μl of the diluted conditioned media was added to theBaF3/KZ134/Zalpha11 cells. The assay using the conditioned media wasdone in parallel on untransfected BaF3/KZ134 cells as a control. Thetotal assay volume was 200 μl. The assay plates were incubated at 37°C., 5% CO₂ for 24 hours at which time the cells were pelleted bycentrifugation at 2000 rpm for 10 min., and the media was aspirated and25 μl of lysis buffer (Promega) was added. After 10 minutes at roomtemperature, the plates were measured for activation of the STATreporter construct by reading them on a luminometer (LabsystemsLuminoskan, model RS) which added 40 μl of luciferase assay substrate(Promega) at a five second integration.

Results confirmed the STAT reporter response of the BaF3/KZ134/Zalpha11cells to the human zalpha11 Ligand. The response, as measured, wasapproximately 50 fold over media-only control at the 50% concentration.STAT activation in response to human zalpha11 Ligand was absent in theuntransfected BaF3/KZ134 control cells, showing that the response ismediated through the Zalpha11 receptor.

Results also confirmed the STAT reporter response of theBaF3/KZ134/Zalpha11 cells to the mouse zalpha11 Ligand. The response, asmeasured, was approximately 40 fold over media-only control at the 50%concentration. Moreover, STAT activation in response to mouse zalpha11Ligand was evident (about 5-fold) on the untransfected BaF/KZ134 controlcells, suggesting that the murine BaF3 cells may have endogenous mousereceptor.

Example 20 Mouse Zalpha11 Ligand is Active in Mouse Bone Marrow Assay

A. Isolation of Non-Adherent Low Density Marrow Cells

Fresh mouse femur aspirate (marrow) was obtained from 6-10 week old maleBalb/C or C57BL/6 mice. The marrow was then washed with RPMI+10% FBS(JRH, Lenexa Kans.; Hyclone, Logan Utah) and suspended in RPMI+10% FBSas a whole marrow cell suspension. The whole marrow cell suspension wasthen subjected to a density gradient (Nycoprep, 1.077, Animal; GibcoBRL) to enrich for low density, mostly mononuclear, cells as follows:The whole marrow cell suspension (About 8 ml) was carefully pipeted ontop of about 5 ml Nycoprep gradient solution in a 15 ml conical tube,and then centrifuged at 600× g for 20 minutes. The interface layer,containing the low density mononuclear cells, was then removed, washedwith excess RPMI+10% FBS, and pelleted by centrifugation at 400× g for5-10 minutes. This pellet was resuspended in RPMI+10% FBS and plated ina T-75 flask at approximately 10⁶ cells/ml, and incubated at 37° C. 5%CO₂ for approximately 2 hours. The resulting cells in suspension wereNon-Adherent Low Density (NA LD) Marrow Cells.

B. 96-Well Assay

NA LD Mouse Marrow Cells were plated at 25,000 to 45,000 cells/well in96 well tissue culture plates in RPMI+10% FBS+1 ng/mL mouse Stem CellFactor (mSCF) (R&D Systems, Minneapolis, Minn.), plus 5% conditionedmedium from one of the following: (1) BHK 570 cells expressing mousezalpha11 Ligand (SEQ ID NO:47), (2) BHK 570 cells expressing humanzalpha11 Ligand (SEQ ID NO:10), or (3) control BHK 570 cells containingvector and not expressing either Ligand. These cells were then subjectedto a variety of cytokine treatments to test for expansion ordifferentiation of hematopoietic cells from the marrow. To test, theplated NA LD mouse marrow cells were subjected to human Interleukin-15(hIL-15) (R&D Systems), or one of a panel of other cytokines (R&DSystems). Serial dilution of hIl-15, or the other cytokines, weretested, with 2-fold serial dilution from about 50 ng/ml down to about6025 ng/ml concentration. After 8 to 12 days the 96-well assays werescored for cell proliferation by Alamar blue assay as described inExample 2.

C. Results from the 96-Well NA LD Mouse Marrow Assay

Conditioned media from the BHK cells expressing both mouse and humanzalpha11 Ligand acted in synergy with hIL-15 to promote the expansion ofa population of hematopoietic cells in the NA LD mouse marrow. Thisexpansion of hematopoietic cells was not shown with control BHKconditioned medium plus IL-15. The population hematopoietic cellsexpanded by the mouse zalpha11 Ligand with hIL-15, and thosehematopoietic cells expanded by the human zalpha11 Ligand with hIL-15,were further propagated in cell culture. These hematopoietic cells werestained with a Phycoerythrin labeled anti-Pan NK cell antibody(Pharmingen) and subjected to flow cytometry analysis, whichdemonstrated that the expanded cells stained positively for this naturalkiller (NK) cell marker.

The same 96-well assay was run, using fresh human marrow cells boughtfrom Poietic Technologies, Gaithersburg, Md. Again, in conjunction withIL-15, the mouse and human zalpha11 Ligand expanded a hematopoietic cellpopulation that stained positively for the NK cell marker using theantibody disclosed above.

The soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ can be used in this assayto measure binding, antagonist or inhibitory effects of the solublezalpha11 receptor or soluble zalpha11 heterodimeric polypeptide, such assoluble zalpha11/IL-2Rγ on the zalpha11 Ligand.

Example 21 Purification of Zalpha11-MBP Receptor

Unless otherwise stated, all operations were carried out at 4° C. Thefollowing procedure was used for purifying human (or mouse) zalpha11-MBPsoluble receptor fusions from E. Coli (Example 8). Pre-spun frozen E.Coli paste was thawed and diluted into 2 liters of Buffer B (0.02 M TRIS(EM Science); 0.2 M NaCl (Mallincrodt); 0.01 M 2-mercapto-ethanol (EMScience); pH 8.0; with 5 mg/l Pepstatin A (Boehringer Mannheim); 5 mg/lAprotinin (Boerhinger Mannheim); and 1 mg/l PMSF (Fluka)) plus 1-2 ml ofan anti-foaming reagent AF289 antifoam (Sigma). The mixture wasprocessed in a pre-chilled French Press cell disrupter (Constant SystemsLTD) with 20-30 kPSI.

The lysate was then centrifuged at 18,000× g for 45 minutes at 4° C. andthe supernatant retained. A 200 ml slurry of Amylose resin (New EnglandBioLabs), pre-equilibrated in Buffer A (0.02 M TRIS (EM Science); 0.2 MNaCl (Mallincrodt); 0.01 M 2-mercapto-ethanol (EM Science); pH 8.0), wasadded to the lysate supernatant and incubated overnight in 21 rollerbottles to allow for maximum batch absorption of the MBP fusion protein.The resin was washed in batch column format for ≧5 column volumes withBuffer A, then batch eluted with Buffer C (Buffer A with 0.02 M Maltose(Sigma). Crude fractions were collected and monitored by absorbance 280nm.

The eluted protein was analyzed by SDS NuPAGE (NOVEX) Coomassie (Sigma)staining. Sample and bulk protein were stored at −80° C.

Example 22 Activity of Human and Mouse Zalpha11 Ligand Expanded Cellsand Mature Murine NK Cells in NK Cell Cytotoxicity Assays

A. NK Cell Assay

NK cell-mediated target cytolysis was examined by a standard⁵¹Cr-release assay. Target cells (K562 cells (ATCC No. CCL-243) in humanassays, and YAC-1 cells (ATCC No. TIB-160) in mouse assays) lackexpression of major histocompatability complex (MHC) molecules,rendering them susceptible to NK cell-mediated lysis. A negative controltarget cell line in mouse assays is the MHC⁺ thymoma EL4 (ATCC No.TIB-39). We grew K562, EL4, and YAC-1 cells in RP10 medium (standardRPMI 1640 (Gibco/BRL, Grand Island, N.Y.) supplemented with 10% FBS(Hyclone, Logan, Utah), as well as 4 mM glutamine (Gibco/BRL), 100I.U./ml penicillin+100 MCG/ml streptomycin (Gibco/BRL), 50 μMβ-mercaptoethanol (Gibco/BRL) and 10 mM HEPES buffer (Gibco/BRL). On theday of assay, 1-2×10⁶ target cells were harvested and resuspended at2.5-5×10⁶ cells/ml in RP10 medium. We added 50-100 μl of 5 mCi/ml⁵¹Cr-sodium chromate (NEN, Boston, Mass.) directly to the cells andincubated them for 1 hour at 37° C., then washed them twice with 12 mlof PBS and resuspended them in 2 ml of RP10 medium. After counting thecells on a hemacytometer, the target cells were diluted to 0.5-1×10⁵cells/ml and 100 μl (0.5-1×10⁴ cells) were mixed with effector cells asdescribed below.

In human assays, effector cells were prepared from selected and expandedhuman CD34⁺ BM cells which were harvested, washed, counted, mixed atvarious concentrations with ⁵¹Cr-labeled target cells in 96-well roundbottomed plates, and incubated for 4 hours at 37° C. After co-incubationof effector cells and the labeled target cells, half of the supernatantfrom each well was collected and counted in a gamma counter for 1min/sample. The percentage of specific ⁵¹Cr release was calculated fromthe formula 100×(X−Y)/(Z−Y), where X is ⁵¹Cr release in the presence ofeffector cells, Y is the spontaneous release in the absence ofeffectors, and Z is the total ⁵¹Cr release from target cells incubatedwith 0.5% Triton X-100. Data were plotted as the % specific lysis versusthe effector-to-target ratio in each well.

B. Activity of Human Zalpha11 Ligand Expanded Cells

Isolated CD34⁺ human HPCs cultured with flt3+/−zalpha11 Ligand andflt3+IL-15+/−zalpha11 Ligand, were harvested the cells on day 15 toassess their capacity to lyse MHC K562 cells in a standard ⁵¹Cr-releaseassay as described above, and to analyze their surface phenotype by flowcytometry. As expected from previous reports (Mrozek, E et al., Blood87:2632-2640, 1996; and Yu, H et al., Blood 92:3647-3657, 1998),simultaneous addition of IL-15 and flt3L did induce the outgrowth of asmall population of CD56⁺ cells. Interestingly, although BM cellscultured simultaneously with zalpha11 Ligand and flt3L did not expandsignificantly, there was a significant increase in total cell numbers incultures containing a combination of flt3L, zalpha11 Ligand and IL-15.

For an assessment of the surface phenotype of these human BM cultures,we stained small aliquots of the cells for 3-color flow cytometricanalysis with anti-CD3-FITC, anti-CD56-PE and anti-CD16-CyChrome mAbs(all from PharMingen, San Diego, Calif.) and analyzed them on aFACSCalibur using CellQuest software (Becton Dickinson, Mountain View,Calif.). This flow cytometric analysis confirmed that the cells growingout of these cultures were differentiated NK cells, as they were largeand granular and expressed both CD56 and CD16, and were CD3⁻ (Lanier, LL Annu. Rev. Immunol. 16:359-393, 1998). Furthermore, these cellsexhibited significantly higher effector function than those cells grownwith IL-15 and flt3. More specifically, cells grown in all threecytokines lysed more than 40% of the K562 targets at aneffector-to-target ratio (E:T) of 1.5, whereas cells grown inIL-15+flt3L lysed fewer than 5% of the targets at an E:T of 2. Thesedata demonstrate that, in combination with IL-15, zalpha11 Ligand(commonly owned U.S. patent application Ser. No. 09/522,217) stimulatesthe differentiation of NK cells from CD34⁺ BM cells.

C. Activity of Mouse Zalpha11 Ligand Expanded Cells

To test the effects of mouse zalpha11 Ligand (commonly owned U.S. patentapplication Ser. No. 09/522,217) on murine hematopoietic progenitorcells, purified Lineage-negative (Lin−) bone marrow cells from C57B1/6mice were expanded in flt3+IL-15+/−zalpha11 Ligand. On day 6 of culture,the cells (“effectors”) were harvested and counted, then resuspended in0.4 ml of RP10 medium (Example 22A). Two aliquots (0.15 ml each) of eachsample expanded with or without zalpha11 Ligand (Example 22A) werediluted serially 3-fold in duplicate in 96-well round bottomed plates,for a total of 6 wells of 100 μl each. The remaining 100 μl of cellswere stained for NK cell surface markers with FITC-anti-2B4 andPE-anti-DX5 mAbs (PharMingen) and analyzed by flow cytometry. Each groupof cells exposed to flt3+IL-15 with or without the presence of mousezalpha11 Ligand had similar fractions of 2B4+DX5+ cells, ranging from65-75% positive for both NK markers.

For the NK lysis assay, target cells (YAC-1 and EL4) were labeled with⁵¹Cr as described above. After counting the target cells on ahemacytometer, the target cells were diluted to 0.5-1×10⁵ cells/ml and100 μl of YAC-1 or EL4 (0.5-1×10⁴ cells) were mixed with 100 μl effectorcells and incubated for 4 hours at 37° C. Specific lysis was determinedfor each well as described above.

We found that cells grown in the presence of flt3+IL-15+zalpha11 Ligandexhibited enhanced lytic activity (roughly 2-fold) against the YAC-1targets (but did not kill the MHC⁺ control cell line EL4). At aneffector-to-target ratio (E:T) of 5, NK cells generated in the presenceof all 3 cytokines (zalpha11 Ligand+flt3+IL-15) lysed 12% of the YAC-1cells, whereas those NK cells expanded with flt3+IL-15 lysed 6% of theYAC-1 targets. Subsequent experiments confirmed this trend.

In a second approach to determine the biological activity of zalpha11Ligand on murine NK cells, we isolated immature CD4 CD8 (“doublenegative”, DN) mouse thymocytes using routine methods and cultured themwith IL-15+flt3+IL-7 or IL-15+flt3+IL-2, with or without zalpha11Ligand. On day 6 of culture, the cells were harvested and assayed for NKlytic activity on YAC-1 and EL4 cells as described above. We found thatcells cultured in the presence of zalpha11 Ligand had the greatest lyticactivity in this assay, with enhanced lytic activity over those cellscultured in the presence of the other cytokines. Specifically, DNthymocytes grown with IL-15+flt3+IL-7 killed 18% of the YAC-1 cells atE:T of 24 while cells grown in the presence of IL-15+flt3+IL-7 pluszalpha11 Ligand killed 48% of the targets at the same E:T. DN thymocytesgrown in IL-15+flt3+IL-2 killed 15% of the YAC-1 targets at an E:T of 6,whereas cells grown with these 3 cytokines and zalpha11 Ligand killed35% of the YAC-1 cells at an E:T of 9. Flow cytometry was performed onthe cultured cells one day before the NK lysis assay. As was true forthe bone marrow cultures, despite the proliferative effect of zalpha11Ligand (cell numbers increase approximately 2-fold when zalpha11 Ligandis added), it did not significantly enhance the fraction of DX5⁺ cells(17-20% of total cells in the cultures with IL-7, and 35-46% of total incultures with IL-2). These data imply that zalpha11 Ligand, incombination with IL-15 and flt3, enhances the lytic activity of NK cellsgenerated from murine bone marrow or thymus.

D. Activity of Mouse Zalpha11 Ligand on Mature Murine NK Cells

In order to test the effects of mouse zalpha11 Ligand on mature NKcells, we isolated spleens from four 5-week old C57B1/6 mice (JacksonLaboratories, Bar Harbor, Me.) and mashed them with frosted-end glassslides to create a cell suspension. Red blood cells were removed byhypotonic lysis as follows: cells were pelleted and the supernatantremoved by aspiration. We disrupted the pellet with gentle vortexing,then added 900 μl of sterile water while shaking, followed quickly (lessthan 5 sec later) by 100 μl of 10×HBSS (Gibco/BRL). The cells were thenresuspended in 10 ml of 1×HBSS and debris was removed by passing thecells over a nylon mesh-lined cell strainer (Falcon). These RBC-depletedspleen cells were then pelleted and resuspended in MACS buffer (PBS+1%BSA+2mM EDTA) and counted. We stained 300×10⁶ of the cells withanti-DX5-coated magnetic beads (Miltenyi Biotec) and positively selectedDX5⁺ NK cells over a MACS VS+ separation column, according to themanufacturer's instructions, leading to the recovery of 8.4×10⁶ DX5⁻cells and 251×10⁶ DX5⁻ cells. Each of these groups of cells werecultured in 24-well plates (0.67×10⁶ cells/well, 2 wells per treatmentcondition) in RP10 medium (Example 22A) alone or with 1) 30 ng/ml mousezalpha11 Ligand (commonly owned U.S. patent application Ser. No.09/522,217), 2) 30 ng/ml recombinant mouse IL-2 (R&D Systems, Inc.,Minneapolis, Minn.), 3) 30 ng/ml recombinant human IL-15 (R&D), 4) 30ng/ml each of mouse zalpha11 Ligand and hIL-15, or 5) 30 ng/ml each ofmIL-2 and hIL-15. The cells were harvested after 21 hours, washed, andresuspended in RP10 medium and counted. The cells were then assayed fortheir ability to lyse ⁵¹Cr-labeled YAC-1 or EL4 targets cells, asdescribed in Example 22A.

In general, there was little NK activity from the DX5⁻ (non-NK cells)groups, but the DX5⁻ cells cultured with zalpha11 Ligand and hIL-15 didlyse 25% of the YAC-1 target cells at an E:T of 82. By comparison, DX5⁻cells cultured with hIL-15 alone lysed 14% of the YAC-1 targets at anE:T of 110. This suggests that zalpha11 Ligand and IL-15 are actingtogether on the residual NK1.1⁺ NK cells in this cell preparation. Asfor the DX5⁺ cell preparation, treatment with mouse zalpha11 Ligandalone did not significantly increase their effector function (theirlysis of YAC-1 cells was similar to the untreated group). As expected,both IL-2 and IL-15 significantly improved NK activity. The highestlevel of lysis, however, was detected in the group treated with zalpha11Ligand and hIL-15 (65% lysis of YAC-1 cells at an E:T of 3.3, vs. 45%lysis at an E:T of 4 for the hIL-15 treatment group). Taken together,these results suggest that although zalpha11 Ligand alone may notincrease NK cell lysis activity, it does enhance NK lysis activity ofmature NK cells, when administered with IL-15.

The soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ can be used in this assayto measure binding, antagonist or inhibitory effects of the solublezalpha11 receptor or soluble zalpha11 heterodimeric polypeptide, such assoluble zalpha11/IL-2Rγ on the zalpha11 Ligand.

Example 23 Zalpha11 Ligand Proliferation of Human and Mouse T-Cells in aT-cell Proliferation Assay

A. Murine Zalpha11 Ligand Proliferation of Mouse T-Cells

T cells from C57B1/6 mice (Jackson Laboratories, Bar Harbor, Me.) wereisolated from pooled splenocytes and lymphocytes from axillary,brachial, inguinal, cervical, and mesenteric lymph nodes (LNs). Spleenswere mashed with frosted-end glass slides to create a cell suspension.LNs were teased apart with forceps and passed through a cell strainer toremove debris. Pooled splenocytes and LN cells were separated into CD8⁺and CD4⁺ subsets using two successive MACS magnetic separation columns,according to the manufacturer's instructions (Miltenyi Biotec, Auburn,Calif.). Whole thymocytes were collected from the same mice.

Cells were cultured at 3×10⁵ cells/well (thymocytes) or 10⁵ cells/well(mature T cells) with increasing concentrations of purified murinezalpha11 Ligand (0-30 ng/ml) (commonly owned U.S. patent applicationSer. No. 09/522,217) in 96-well flat bottomed plates pre-coatedovernight at 4° C. with various concentrations of anti-CD3 mAb 2C11(PharMingen) for 3 days at 37° C. The anti-CD3 antibody served toactivate the murine T-cells through the T-cell receptor. Each well waspulsed with 1 μCi ³H-thymidine on day 2 and plates were harvested andcounted 16 hours later to assess proliferation.

When we tested zalpha11 Ligand in T cell proliferation assays, we foundthat it co-stimulated anti-CD3-activated murine thymocytes, leading toan accelerated outgrowth of CD8⁺CD4⁻ cells (the majority of thethymocytes cultured with anti-CD3+zalpha11 Ligand were CD8⁺ CD4⁻ by day3 of culture, while cells cultured with anti-CD3 alone did notsignificantly skew to this phenotype until day 5). We did not observesignificant levels of proliferation of thymocytes to zalpha11 Ligand inthe absence of anti-CD3.

Interestingly, when we assayed mature peripheral murine T cells fortheir ability to respond to zalpha11 Ligand+anti-CD3, we found that onlythe CD8⁺, but not the CD4⁺ subset, responded in a dose-dependent mannerto zalpha11 Ligand. We also observed weak but reproducible proliferationof CD8⁺ cells (but not CD4⁺ cells) in response to zalpha11 Ligand alone.Interestingly, this was not observed for human T cells (see Example 22B,below).

B. Human Zalpha11 Ligand Proliferation of Human T-Cells

Human CD4+ and CD8+ T cells were isolated from PBMC as described inExample 14. Cells were cultured at about 10⁵ cells/well with increasingconcentrations of purified human zalpha11 Ligand (0-50 ng/ml) (commonlyowned U.S. patent application Ser. No. 09/522,217) in 96-well flatbottomed plates pre-coated overnight at 4° C. with variousconcentrations of anti-human CD3 mAb UCHT1 (PharMingen) for 3 days at37° C. Each well was pulsed with 1 uCi ³H-thymidine on day 2 and plateswere harvested and counted 16 hours later. Unlike our results with mouseT cells, our preliminary data suggests that human zalpha11 Ligandco-stimulates CD4+, but not CD8+, human T cells in a dose-dependentfashion.

The soluble zalpha11 receptor or soluble zalpha11 heterodimericpolypeptide, such as soluble zalpha11/IL-2Rγ can be used in this assayto measure binding, antagonist or inhibitory effects of the solublezalpha11 receptor or soluble zalpha11 heterodimeric polypeptide, such assoluble zalpha11/IL-2Rγ on the zalpha11 Ligand

Example 24 Human Zalpha11 Receptor Monoclonal Antibodies

Zalpha11 receptor Monoclonal antibodies were prepared by immunizing 5male BalbC mice (Harlan Sprague Dawley, Indianapolis, Ind.) with thepurified recombinant protein, huzalpha11-CEE-BHK (Example 6). The micewere each given an initial intraperitoneal (IP) injection of 20 mg ofpurified protein in Complete Freund's Adjuvant (Pierce, Rockford, Ill.)followed by booster IP injections of 10 mg purified protein inIncomplete Freund's Adjuvant every two weeks. Seven to ten days afterthe administration of the third booster injection, the animals were bledand the serum was collected.

The mouse sera samples raised to the huzalpha11-CEE-BHK werecharacterized by an ELISA titer check using purified recombinant CHOhuzalpha11-Fc protein (Example 10C) as an antibody target. One mouseserum sample had titer to the specific antibody target at a dilution of1:1,000,000 (1:1E6). Four mouse serum samples had titer to the specificantibody target at a dilution of 1:100,000 (1:1E5).

Splenocytes were harvested from the 4 high-titer mice and fused tomurine SP2/0 myeloma cells using PEG 1500 (Boerhinger Mannheim, UK) intwo separate fusion procedures using a 4:1 fusion ratio of splenocytesto myeloma cells (Antibodies: A Laboratory Manual, E. Harlow and D.Lane, Cold Spring Harbor Press). Following 10 days growth post-fusion,specific antibody-producing hybridomas were identified by ELISA usingpurified recombinant BHK human zalpha11-Fc4 protein (Example 6C) as anantibody target and by FACS using Baf3 cells expressing the huzalpha11sequence (Example 2) as an antibody target. The resulting 4 hybridomaspositive by both methods were cloned three times by limiting dilution.The antibodies were designated: 249.28.2.1.2.2; 247.10.2.15.4.6;249.19.2.2.3.5; and 249.15.2.4.2.7.

Example 25 Zalpha11 Receptor Purified Recombinant Human ProteinDose-Response Study in Normal Mice

A. Summary

Normal nine week old female C57B1/6 (Harlan Sprague Dawley,Indianapolis, Ind.) mice were treated by intraperitoneal injection oncedaily for seven days with one of three dose levels of purifiedrecombinant human zalpha11-Fc4 soluble receptor (Example 6C) (5, 50 or250 μg/mouse/day) or PBS vehicle plus 250 μg per dose of BSA. Bodyweights were monitored every other day. On day seven the five mice fromthe highest dose group and five of the vehicle control group weresacrificed. Blood, bone marrow and tissues were harvested and analyzed.The remaining mice were sacrificed and harvests done the following day.Potential perturbations in lymphoid tissues were examined, as well asgeneral physiologic and toxicologic parameters.

There was no clinical evidence of toxicity. Liver, kidney, spleen,thymus and brain were weighed, and there were no differences between thetreatment groups in organ weights. No histologic changes were found inthe examined tissues.

B. Dosing Solution Preparation

Purified recombinant human zalpha11 receptor-FC4 fusion protein(zalpha11-FC4) (Example 6C) was diluted into sterile phosphate bufferedsaline (PBS) (GibcoBRL, Grand Island, N.Y.) at concentrations to deliver5, 50 or 250 micrograms of protein in 0.1 ml of PBS vehicle. Bovineserum albumin (BSA) (Sigma, St. Louis, Mo.) was dissolved in PBS to makea 250 μg dose per 0.1 ml then filtered through an 0.2 μm syringe-tipfilter for the vehicle control treatment. The solutions for daily dosingwere made on Day 0, aliquotted and frozen in a frosty −20° C. freezerfor use. On the day of administration the appropriate aliquots werethawed and 0.1 ml of solution was injected intraperitoneally atapproximately mid-morning each day for seven days.

C. Study Design

The mice were nine weeks old at the start of the study. Eachzalpha11-FC4 treatment group consisted of five mice; the control grouphad 10 mice. The mice in the highest dose and half of the control micewere sacrificed the day after the last of seven treatments (Day 7). Thetwo lower dose and remaining control groups were sacrificed thefollowing day (Day 8).

The body weights of the mice were recorded every other day duringtreatment. There was no difference in weight gain between the treatmentgroups over the week of treatment.

At sacrifice, tissues harvested to assess lymphocyte populations by FACSanalysis included bone marrow, thymus and spleen. Flow Cytometryanalysis of the lymphoid organs and bone marrow was performed with theFACSCalibur, (Becton Dickinson, Mansfield, Mass.). The tissues harvestedfor histologic examination for signs of toxicity of the proteinincluded: spleen, thymus, liver, kidney, adrenal gland, mesenteric lymphnode, duodenum, pancreas, jejunum, sternum, uterus, ovaries, urinary andgall bladders, salivary gland, heart and lungs. All tissues fixed forhistology were kept at 4° C. overnight in 10% Normal Buffered Saline(Surgipath, Richmond, Ill.). The following day the NBF was replaced with70% ethanol and the tissues returned to 4° C. until processing forhistology.

The tissues were processed and stained for H&E analysis in house, thensent to the contract pathologist, David Fairchild. Blood was collectedfor complete blood cell counts and serum chemistry profiles. The CBC'swere done in-house with the Cell Dyn 3500 Hematology Analyzer (AbbottDiagnostics Division, Abbott Park, Ill.). The serum was kept frozen in afrosty −20° C. freezer until submission to Phoenix Central Laboratory(Everett, Wash.) for complete serum chemistry panels. To comparemyeloid:erythroid ratios between the 250 μg dose groups of zalpha11R andBSA, an aliquot of the bone marrow from one femur was applied toCytoSpin slides (CYTOSPIN 3 CYTOCENTRIFUGE and CYTO SLIDES, Shandon,Pittsburgh, Pa.). The bone marrow slides were analyzed at PhoenixCentral Laboratories.

D. Study Results

There were no apparent clinical indications of physiologic effects or oftoxicity of rh-zalpha11R-FC4 fusion protein at doses tested (250 μg/dayor lower). Body weights remained normal for the duration of thetreatments. Red blood cell and platelet counts were normal. There weretwo mice in the 250 μg dose zalpha11-FC4 group whose differential WBCcount revealed a possible elevation in the percentage of monocytes,however the other three mice in the group had monocyte percentagesequivalent to the average of the control mice. The differential whiteblood cell monocyte count difference is not considered a significantfinding. There were no other differences in complete blood counts. Thebone marrow cytology did not reveal a shift in the myeloid and erythroidprogenitor populations, and all cell types present appeared normal. Allthe standard serum chemistry parameters were in normal ranges. Therewere no differences between the treatment groups in the weights of thethymus, spleen, kidney, liver or brain. Histologic evaluation of thefollowing tissues showed no evidence of abnormalities: thymus, spleen,liver, kidney, adrenal gland, duodenum, pancreas, jejunum, caecum,colon, mesenteric lymph nodes, uterus, ovaries, salivary gland, heart,trachea, lung and brain. The absence of physiologic effects in normalmice indicates that the zalpha11 soluble receptor has low toxicity invivo, which is desirable for a therapeutic agent.

Example 26 Zalpha11 Ligand-Dependent Proliferation of B-Cell CellsStimulated Anti-CD40 or Anti-IgM

A. Purification of Human B Cells

A vial containing 1×10⁸ frozen, apheresed human peripheral bloodmononuclear cells (PBMCs) was quickly thawed in a 37° C. water bath andresuspended in 25 ml B cell medium (RPMI Medium 1640 (JRH Biosciences.Lenexa, Kans.), 10% Heat inactivated fetal bovine serum, 5% L-glutamine,5% Pen/Strep) (Gibco BRL)) in a 50 ml tube (Falcon VWR, Seattle, Wash.).Cells were tested for viability using Trypan Blue (Gibco BRL). Tenmilliliters of Ficoll/Hypaque Plus (Pharmacia LKB Biotechnology Inc.,Piscataway, N.J.) was layered under the cell suspension and spun for 30minutes at 1800 rpm and allowed to stop with the brake off. Theinterface was then removed and transferred to a fresh 50 ml Falcon tube,brought up to a final volume of 40 ml with PBS and spun for 10 minutesat 1200 rpm with the brake on. The viability of the isolated cells wastested using Trypan Blue. Alternately fresh drawn human blood wasdiluted 1:1 with PBS (Gibco BRL) and layered over Ficoll/Hypaque Plus(Pharmacia), spun and washed as above. Cells isolated from either freshor frozen sources gave equivalent results.

B cells were purified from the Ficoll floated peripheral blood cells ofnormal human donors (above) with anti-CD19 magnetic beads (MiltenyiBiotec, Auburn, Calif.) following the manufacturer's instructions. Thepurity of the resulting preparations was monitored by flow cytometricanalysis with anti-CD22 FITC Ab (Pharmingen, San Diego, Calif.). B cellpreparations were typically >90% pure.

B. Purification of Murine B Cells

A suspension of murine splenocytes was prepared by teasing adult C57B1/6mouse (Charles River Laboratories, Wilmington, Mass.) spleens apart withbent needles in B cell medium. RBCs were removed by hypotonic lysis.CD43 positive cells were removed with CD43 magnetic beads (MiltenyiBiotec) following the manufacturer's instructions. The purity of theresulting preparations was monitored by flow cytometric analysis withanti-CD45R FITC Ab (Pharmingen). B cell preparations were typically >90%pure.

C. Proliferation of Anti-CD40-Stimulated B-Cells in the Presence ofHuman or Murine Zalpha11 Ligand

The B cells from either the human or mouse source were resuspended at afinal concentration of 1×10⁶ cells/ml in B cell medium and plated at 100μl/well in a 96 well U bottom plate (Falcon, VWR) containing variousstimulation conditions to bring the final volume to 200 μl/well. Foranti-CD40 stimulation human cultures were supplemented with 1 ug/mlanti-human CD40 (Genzyme, Cambridge, Mass.) and mouse cultures weresupplemented with 1 μg/ml anti-murine CD40 (Serotec, UK). Human ormurine zalpha11 Ligand (commonly owned U.S. patent application Ser. No.09/522,217) was added at dilutions ranging from 1 pg/ml-100 ng/ml asappropriate. The specificity of the effect of zalpha11 Ligand wasconfirmed by inhibition of zalpha11 Ligand with 25 mg/ml soluble humanzalpha11CEE (Example 6A). All treatments were performed in triplicate.The cells were then incubated at 37° C. in a humidified incubator for120 hours (human) or 72 hours (mouse). Sixteen hours prior toharvesting, 1 μCi ³H-thymidine (Amersham, Piscataway, N.J.) was added toall wells to assess whether the B-cells had proliferated. The cells wereharvested into a 96 well filter plate (UniFilter GF/C, Packard, Meriden,Conn.) using a cell harvester (Packard) and collected according tomanufacturer's instructions. The plates were dried at 55° C. for 20-30minutes and the bottom of the wells were sealed with an opaque platesealer. To each well was added 0.25 ml of scintillation fluid(Microscint-O, Packard) and the plate was read using a TopCountMicroplate Scintillation Counter (Packard).

Incubation with Zalpha11 Ligand at concentrations of 3 ng/ml or moreenhanced the proliferation induced by soluble anti-CD40 in a dosedependent manner in both murine and human B cells by as much as 30 fold.The murine and human B cells responded equally as well to theirrespective zalpha11 Ligand. In both species, the stimulation wasspecific to zalpha11 Ligand, as it was reversed by the presence ofsoluble zalpha11 receptor in the culture.

D. Proliferation of Anti-IgM-Stimulated B-Cells in the Presence of Humanor Murine Zalpha11 Ligand

The B cells from either human or mouse source as described above (partsA and B) were plated as described above (part C). For anti-IgMstimulation of human cells the plates were pre-coated overnight with 10mg/ml F(ab′)₂ anti-human IgM Abs (Southern Biotech Associates,Birmingham, Ala.) and washed with sterile media just prior to use. Thecultures were supplemented with 0-10 ng/ml hu rIL-4 (R&D Systems,Minneapolis, Minn.). For anti-IgM stimulation of murine cells solubleanti-IgM (Biosource, Camarillo, Calif.) was added to the cultures at 10mg/ml. To each of the preceding anti-IgM/IL-4 conditions, human ormurine Zalpha11 ligand was added at dilutions ranging from 1 pg/ml-100ng/ml as described above. The specificity of the effect of zalpha11Ligand was confirmed by inhibition with soluble human zalpha11 receptoras described above (Part C). All treatments were performed intriplicate. The cells were incubated, labeled with ³H-thymidine,harvested, and analyzed as described in part C above.

Incubation with Zalpha11 ligand at concentrations of 0.3 ng/ml or moreinhibited the proliferation induced by insoluble anti-IgM (mouse) oranti-IgM and IL-4 (human) in a dose-dependent manner. This inhibitionwas specific to zalpha11 Ligand, as it was reversed by the presence ofsoluble zalpha11 receptor in the culture.

E. Anti-CD40 B Cell Proliferation Requires IL-2 Receptor Gamma

Murine B-cells were purified and stimulated with anti-CD40 monoclonalantibody as described in Example 26B and C above. The co-stimulationinduced by murine zalpha11 Ligand was completely blocked by the additionof anti-IL-2 receptor gamma (IL-2Rγ) monoclonal antibodies that blockIL-2γ utilization. The antibodies 3E12 and TUG/m2 (PharMingen, SanDiego, Calif.) were included in the proliferation assay at 50 μg/ml.These results demonstrate that the IL-2Rγ in B cells is physiologicallyinvolved with the zalpha11 Ligand stimulation of B cells. Moreover,these results provide indirect functional support in vivo for thefinding that the IL-2Rγ heterodimerizes with the zalpha11 receptor invitro (Example 27, below).

F. The Effects of Zalpha11 Ligand on B Cells Are Inhibited by SolubleZalpha11 Receptor Constructs

Murine B-cells were purified and stimulated with anti-CD40 monoclonalantibody or anti-IgM antibodies as described in Example 26C and D above.The effect induced by murine zalpha11 Ligand was completely blocked bythe addition of either purified huzalpha11R: IL-2Rγ a heterodimericsoluble receptor (Example 28), or a mu-zalpha11-Fc, a homodimericsoluble receptor (Example 6C). Again, these results provide furtherfunctional support for the finding that the IL-2Rγ heterodimerizes withthe zalpha11 receptor (Example 27, below), and acts as an antagonist tothe zalpha11 Ligand's effect on B-cells.

Example 27 Human Zalpha11 Receptor Heterodimerizes with IL-2 ReceptorGamma

A. Assay Using Conditioned Media from Transfected BHK-570 CellsExpressing Human Zalpha11 Ligand

Soluble human zalpha11 receptor zalpha11CFLAG (Example 6B), or gp130(Hibi, M. et al., Cell 63:1149-1157, 1990) were biotinylated by reactionwith a five-fold molar excess of sulfo-NHS-LC-Biotin (Pierce, Inc.,Rockford, Ill.) according to the manufacturer's protocol. Solublezalpha11 receptor and soluble IL-2 receptor-γ (sIL-2Rγ) (R&D Systems,Minneapolis, Minn.) were labeled with a five fold molar excess ofRu-BPY-NHS (Igen, Inc., Gaithersburg, Md.) according to manufacturer'sprotocol. The biotinylated and Ru-BPY-NHS-labeled forms of the solublezalpha11 receptor were respectively designated Bio-zalpha11 receptor andRu-zalpha11; the biotinylated and Ru-BPY-NHS-labeled forms of thesoluble IL-2Rγ were respectively designated Bio-IL2Rγ and Ru-IL2Rγ.

For initial receptor binding characterization of human zalpha11 Ligand,conditioned media from transfected BHK-570 cells expressing humanzalpha11 Ligand or control media from untransfected BHK-570 cells wasused to determine if zalpha11 Ligand could mediate homodimerization ofzalpha11 receptor and if it could mediate the heterodimerization ofzalpha11 receptor with IL-2Rγ or gp130. To do this, 50 □1 of conditionedmedia, from control cells or conditioned media from cells expressingzalpha11 Ligand, was combined with 50 □1 of TBS-B (20 mM Tris, 150 mMNaCl, 1 mg/ml BSA, pH 7.2) containing 400 ng/ml of Ru-zalpha11 receptorand Bio-zalpha11, or 400 ng/ml of Ru-zalpha11 receptor and Bio-gp130, or400 ng/ml of Ru-IL2Rγ and Bio-zAlph11. Following incubation for one hourat room temperature, 30 □g of streptavidin coated, 2.8 mm magnetic beads(Dynal, Inc., Oslo, Norway) were added and the reaction incubated anadditional hour at room temperature. 200 □1 ORIGEN assay buffer (Igen,Inc., Gaithersburg, Md.) was then added and the extent of receptorassociation measured using an M8 ORIGEN analyzer (Igen, Inc.).

Conditioned media containing zalpha11 Ligand caused theheterodimerization of Bio-zalpha11 receptor with Ru-IL2Rγ. No receptordimerization was observed in the presence of control media. Conditionedmedia containing zalpha11 Ligand did not cause the homodimerization ofRU-zalpha11 receptor with Bio-zalpha11 receptor, nor theheterodimerization of Ru-zalpha11 receptor with Bio-gp130.

B. Assay Using Purified Human Zalpha11 Ligand

To assess the ligand specificity of the heterodimerization of zalpha11receptor and IL2Rγ, 50 □1 of TBS-B containing 400 ng/ml of Ru-zalpha11receptor and Bio-zAlph11, or 400 ng/ml Ru-IL2Rγ and Bio-zAlph11 wascombined 50 □1 of TBS-B containing IL-2, IL-4, IL-15 or purified humanzalpha11 Ligand (commonly owned U.S. patent application Ser. No.09/522,217) at concentrations from 133 pg/ml to 300 ng/ml. Followingincubation for one hour a room temperature, 3 □g of streptavidin coated,2.8 mm magnetic beads (Dynal, Inc.) were added and the reactionincubated an additional hour at room temperature. 200 □1 Origlo assaybuffer (Igen, Inc.) was then added and the extent of receptorassociation measured using an M8 Origen analyzer (Igen, Inc.). The humanzalpha11 Ligand caused the heterodimerization of Bio-zalpha11 receptorwith Ru-IL-2Rγ in a dose dependent manner with a half maximalconcentration of 10 ng/ml. No homodimerization of Ru-zalpha11 receptorwith Bio-zalpha11 receptor was observed at any concentration of zalpha11Ligand tested. No homodimerization of Ru-zalpha11 receptor withBio-zalpha11 receptor or heterodimerization of Bio-zalpha11 receptorwith Ru-IL2Rγ was observed with IL-2, IL-4 or IL-15, at any of theconcentrations tested. Thus, the results show that the human zalpha11receptor heterodimerizes specifically with the IL-2 receptor-γ in thepresence of human zalpha11 Ligand, and that the zalpha11 receptor doesnot homodimerize or heterodimerize in the presence of other cytokinestested.

Example 28 Construct for Generating Human Zalpha11 Receptor/IL-2RγHeterodimer

A vector expressing a secreted human hzalpha11/hIL2R gamma heterodimerwas constructed. In this construct, the extracellular domain ofhzalpha11 was fused to the heavy chain of IgG gamma 1 (IgGγ1) (SEQ IDNO:16), while the extracellular portion of hIL-2Rγ was fused to a humankappa light chain (human κ light chain) (SEQ ID NO:18).

A. Construction of IgG Gamma 1 and Human κ Light Chain Fusion Vectors

The heavy chain of IgGγ1 was cloned into the Zem229R mammalianexpression vector (ATCC deposit No. 69447) such that any extracellularportion of a receptor having a 5′ EcoRI and 3′ NheI site can be clonedin resulting in an N-terminal extracellular domain-C-terminal IgGγ1fusion. The IgGγ1 fragment used in this construct was made by using PCRto isolate the IgGγ1 sequence from a Clontech hFetal Liver cDNA libraryas a template. A PCR reaction using oligos ZC11,450 (SEQ ID NO:50) andZC11,443 (SEQ ID NO:51) was run as follows: 40 cycles of 94° C. for 60sec., 53° C. for 60 sec., and 72° C. for 120 sec.; and 72° C. for 7 min.PCR products were separated by agarose gel electrophoresis and purifiedusing a QiaQuick™ (Qiagen) gel extraction kit. The isolated, 990 bp, DNAfragment was digested with Mlu I and EcoRI (Boerhinger-Mannheim),ethanol precipitated and ligated with oligos ZC11,440 (SEQ ID NO:52) andZC11,441 (SEQ ID NO:53), which comprise an MluI/EcoRI linker, intoZem229R previously digested with and EcoRI using standard molecularbiology techniques disclosed herein. This generic cloning vector wascalled Vector#76 hIgGgamma1 w/Ch1 #786 Zem229R (Vector #76). Thepolynucleotide sequence of the extracellular domain of hzalpha11 fusedto the heavy chain of IgG gamma 1 is shown in SEQ ID NO:15 and thecorresponding polypeptide sequence shown in SEQ ID NO:16.

The human κ light chain was cloned in the Zem228R mammalian expressionvector (ATCC deposit No. 69446) such that any extracellular portion of areceptor having a 5′ EcoRI site and a 3′ KpnI site can be cloned inresulting in a N-terminal extracellular domain-C-terminal human κ lightchain fusion. The human κ light chain fragment used in this constructwas made by using PCR to isolate the human κ light chain sequence fromthe same Clontech hFetal Liver cDNA library used above. A PCR reactionusing oligos ZC11,501 (SEQ ID NO:54) and ZC11,451 (SEQ ID NO:55) was rununder conditions described above. PCR products were separated by agarosegel electrophoresis and purified using a QiaQuick™ (Qiagen) gelextraction kit. The isolated, 315 bp, DNA fragment was digested withMluI and EcoRI (Boerhinger-Mannheim), ethanol precipitated and ligatedwith the MluI/EcoRI linker described above, into Zem228R previouslydigested with and EcoRI using standard molecular biology techniquesdisclosed herein. This generic cloning vector was called Vector #77hKlight #774 Zem228R (Vector #77). The polynucleotide sequence of theextracellular portion of hIL-2Rγ was fused to a human kappa light chainis shown in SEQ ID NO:17 and the corresponding polypeptide sequenceshown in SEQ ID NO:18.

B. Insertion of Zalpha11 Receptor or IL-2Rγ Extracellular Domains IntoFusion Vector Constructs

Using the construction vectors above, a construct having human zalpha11fused to IgGγ1 was made. This construction was done by PCRing humanzalpha11 receptor from a CD4+ bone marrow library (selected, and made inhouse) with oligos ZC24,052 (SEQ ID NO:56) and ZC24,053 (SEQ ID NO:57),under conditions described as follows: 30 cycles of 94° C. for 60 sec.,57° C. for 60 sec., and 72° C. for 120 sec.; and 72° C. for 7 min. Theresulting PCR product was digested with EcoRI and NheI, gel purified, asdescribed herein, and ligated into a previously EcoRI and NheI digestedand band-purified Vector#76 (above). The resulting vector was sequencedto confirm that the human zalpha11/IgG gamma 1 fusion (hzalpha11/Ch1IgG) was correct. The hzalpha11/Ch1 IgG gamma1 vector was called Vector#190.

A separate construct having IL-2Rγ fused to κ light was alsoconstructed. The IL-2Rγ/human κ light chain construction was performedas above by PCRing from the same CD4+ library mentioned above witholigos ZC12,834 (SEQ ID NO:58) and ZC12,831 (SEQ ID NO:59), digestingthe resulting band with EcoRI and KpnI and then ligating this productinto a previously EcoRI and KpnI digested and band-purified Vec#77(above). The resulting vector was sequenced to confirm that the humanIL-2Rγ/human κ light chain fusion (hIL-2Rγ/Klight) was correct. ThishIL-2gamma/Klight #1052 Zem228R vector was called Vector #101.

D. Co-Expression of the Human Zalpha11 and Human IL-2Rγ Receptors

Approximately 16 μg of each of Vectors #190 and #101, above, wereco-transfected into BHK-570 cells (ATCC No. CRL-10314) usingLipofectaminePlus™ reagent (Gibco/BRL), as per manufacturer'sinstructions. The transfected cells were selected for 10 days in DMEM+5%FBS (Gibco/BRL) containing 1 μM of methotrexate (MTX) (Sigma, St. Louis,Mo.) and 0.5 mg/ml G418 (Gibco/BRL) for 10 days. The resulting pool oftransfectants was selected again in 10 μm of MTX and 0.5 mg/ml G418 for10 days.

The resulting pool of doubly-selected cells was used to generateprotein. Three Factories (Nunc, Denmark) of this pool were used togenerate 10 L of serum free conditioned medium. This conditioned mediawas passed over a 1 ml protein-A column and eluted in (10) 750microliter fractions. 4 of these fractions found to have the highestconcentration were pooled and dialyzed (10 kD MW cutoff) against PBS.Finally the dialyzed material was submitted for amino acid analysis(AAA) and found to have a concentration of 227.17 μg/ml AAA. A total of681.5 μg was obtained from this 10 L purification. The purified solublehuman zalpha11 receptor/IL-2Rγ receptor was used to assess its abilityto compete with the human zalpha11 Ligand a BaF3 proliferation assay(Example 29, below).

Example 29 Soluble Human Zalpha11 Receptor/Human IL2 Gamma Receptor-Fcas a Zalpha11 Ligand Antagonist

BaF3 cells stably expressing the human zalpha11 receptor (Example 2)were plated at 5500 cells per well in standard 96-well tissue cultureplates in base medium plus 3 ng/ml human zalpha11 Ligand. Base medium is500 ml RPMI 1640 (JRH Biosciences), 5 ml 100× Sodium Pyruvate (GibcoBRL), 5 ml 100× L-glutamine (Gibco BRL), and 50 ml heat-inactivatedFetal Bovine Serum (FBS) (Hyclone Laboratories). To the cells, adecreasing dose of either purified soluble human zalpha11 receptor-Fchomodimer (Example 6C) or purified soluble human zalpha11 receptor/humanIL2 gamma receptor-Fc heterodimer (Example 27) were added. An AlamarBlue proliferation assay was run and fluorimetry performed as perExample 2B.

The zalpha11 receptor/IL2 gamma receptor-Fc heterodimer inhibited humanzalpha11 Ligand activity in a dose dependent manner, with 0.312 μg/mlable to completely inhibit the activity of 3 ng/ml human zalpha11Ligand. The soluble zalpha11 receptor-Fc homodimer also was able toinhibit zalpha11 Ligand activity in a dose dependent manner, however itrequired about 10 μg/ml of soluble homodimer to completely inhibit theactivity of 3 ng/ml zalpha11 Ligand. These data suggested the zalpha11receptor/IL2 gamma receptor-Fc heterodimer soluble receptor isapproximately 30 to 100 fold more potent than the homodimeric solublezalpha11 receptor in inhibiting human zalpha11 Ligand.

Example 30 Zalpha11 Receptor Distribution

To assess zalpha11 receptor distribution on various cells types, wegenerated both rabbit polyclonal and mouse monoclonal antibodies (mAbs)directed against the human receptor (Example 24 and Example 10) andconjugated these antibodies to biotin for use in flow cytometry. Weinitially used the polyclonal antibodies, which were of relatively lowaffinity, to stain a panel of cell lines: IL-3 dependent murine pre-Bcell line wild-type BaF3 cells (Palacios and Steinmetz, ibid.;Mathey-Prevot et al., ibid.); BaF3 cells transfected with human zalpha11(Example 2); human Burkitt's lymphoma cell lines Raji (ATCC No. CCL-86),Ramos (ATCC No. CRL-1596), RPMI 8226 (ATCC No. CCL-155), and Daudi (ATCCNo. CCL-213); human T cell leukemia cell line Jurkat (ATCC No. TIB-152);human myelomonocytic leukemia cell lines Thp-1 (ATCC No. TIB-202) andU937 (ATCC No. CRL-1593.2); human pro-myelomonocytic cells HL-60 (ATCCNo. CCL-240); murine B cell lymphoma cell line A20 (ATCC No TIB-208);and murine thymoma cell line EL4 (ATCC No. TIB-39).

The cells were harvested, washed once with FACS wash buffer with serum(WBS). WBS consisted of Hank's balanced salt solution (Gibco/BRL)+10 mMHEPES (Gibco/BRL)+1% BSA (Sigma)+10% normal goat serum (GeminiBioproducts, Woodland, Calif.)+10% normal rabbit serum (Sigma); washbuffer (WB) was identical to WBS except that it is serum free. Afterwashing, the cells were resuspended in 100 μl WB containing 10 μg/mlrabbit anti-zalpha11 polyclonal antibodies (Example 10). The cells werekept on ice with Ab for 20 min, then washed with WB and resuspended inWB containing goat anti-rabbit-FITC (BioSource, International),incubated another 20 min on ice, then washed and resuspended in 400 μlWB for analysis on a FACSCalibur flow cytometer (Becton Dickinson).Control samples were stained with the secondary goat anti-rabbit-FITC Abonly. Positive staining was defined as a shift above the staining withsecondary alone. Although the polyclonal antibodies were of lowaffinity, we were reasonably confident that we detected zalpha11expression on the BaF3/zalpha11 transfectant, on all four humanBurkitt's lymphomas (Raji, Ramos, Daudi, and RPMI 8226), and on Jurkat Tcells. Our data with the monocytic cell lines were more ambiguous.Resting (undifferentiated) HL-60 cells did not bind the anti-zalpha11antibodies, but we did detect a positive signal on HL-60 cells activatedfor 24 hours with PMA (Calbiochem, La Jolla, Calif.) which induces HL-60cell differentiation into a monocyte-like cell. We also saw a positivesignal on U937 and Thp-1 cells, although this signal may have been dueto non-specific binding. The polyclonal antibodies weakly cross-reactedon the mouse B cell line A20, but we saw no staining of the EL4 murinethymoma.

The four anti-zalpha11 monoclonal antibodies (Example 24) wereconjugated to biotin, and a subset of the cells described above werescreened for zalpha11 receptor expression (BaF3, BaF3/zalpha11, Raji,Jurkat, and resting HL-60). Cells were harvested, washed, thenresuspended in 100 μl WB containing 15 μg/ml of one of each of the 4biotinylated mAbs. The cells were incubated with mAb for 20 min on ice,then washed with 1.5 ml WB and pelleted in a centrifuge. The supernatantwas removed by aspiration and the pellets were resuspended in 100 μl ofCyChrome-conjugated streptavidin (CyC-SA; PharMingen), then incubated onice for another 20 min and washed and pelleted as before. Control tubescontained cells stained only with CyC-SA. Pellets were resuspended in400 μl WB and flow cytometry performed as above. Positive staining wasdefined as a signal exceeding the background level of staining withCyC-SA alone. Using the BaF3/zalpha11 transfectant as a control, we wereable to rank the 4 mAbs in terms of their respective mean fluorescenceintensities (MFI), which can reflect antibody affinity and/or the extentof biotinylation of the mAbs. The mAbs were ranked as follows, fromhighest to lowest MFI: 249.28.2.1.2.2, 247.10.2.15.4.6, 249.19.2.2.3.5,and 249.15.2.4.2.7. This pattern was essentially the same on both Rajiand Jurkat cells, indicating that zalpha11 is expressed on these B and Tcell lines. The staining patterns on non-activated HL60 cells wereidentical for all the mAbs, and the signal was very weak. We speculatethat this does not reflect actual expression of zalpha11 by this cellline, but rather is a function of non-specific binding of the mouse mAbsto the human cells, probably via Fc-receptors.

Example 31 Reconstitution of Human Zalpha11 Receptor In Vitro

To identify components involved in the zalpha11-signaling complex,receptor reconstitution studies were performed as follows. BHK 570 cells(ATCC No. CRL-10314) transfected, using standard methods describedherein, with the KZ134 luciferase reporter plasmid (Example 19) servedas a bioassay cell line to measure signal transduction response from atransfected zalpha11 receptor complex to the luciferase reporter in thepresence of zalpha11 Ligand. BHK cells do not endogenously express thezalpha11 receptor. The bioassay cell line was transfected with zalpha11receptor alone, or co-transfected with zalpha11 receptor along with oneof a variety of other known receptor subunits. Each receptor subunit wascloned using PCR followed by ligation into appropriate expressionvectors; correct sequence of each construct was confirmed beforetransfection. Cell lines were tested for receptor expression by RT/PCRprior to assays. Receptor complexes tested included: zalpha11 receptoralone; zalpha11 receptor with IL-2Rγ; zalpha11 receptor with IL-2Rγ andIL-2Rβ; zalpha11 receptor with IL-2Rγ and IL-13Rα; zalpha11 receptorwith IL-2Rγ and IL-2Rα; and zalpha11 receptor with IL-2Rγ and IL-4Rα.Each independent receptor complex cell line was assayed in the presenceof human zalpha11 Ligand and luciferase activity measured as describedin Example 19. The untransfected bioassay cell line served as a controlfor the background luciferase activity, and was used as a baseline tocompare signaling by the various receptor complex combinations. In eachcell line containing both zalpha11 receptor and IL-2Rγ, maximalluciferase activity was about two-fold over background in the presenceof zalpha11 Ligand. No increase in signal was observed in the presenceof any other receptor subunit tested (IL-2Rβ, IL-2Rα, IL-4Rα, orIL-13Rα).

Other zalpha11 receptor complexes that can be assessed by this methodinclude combinations of zalpha11 receptor with one or more of theIL-4/IL-13 receptor family receptor components (IL-13Rα′), as well asother Interleukin receptors (e.g., IL-15 Rα, IL-7Rα, IL-9Rα).

Example 32 ¹²⁵I-Labeled Human Zalpha11 Ligand Binding Study in CellLines

25 micrograms of purified human zalpha11 Ligand (commonly owned U.S.patent application Ser. No. 09/522,217) was labeled with 2 mCI ¹²⁵Iusing iodobeads (Pierce, Rockford Ill.), according to manufacturer'sinstructions. This labeled protein was used to assess human zalpha11Ligand binding to human Raji cells (ATCC No. CCL-86), using binding towild-type murine BaF3 cells, and BaF3 cells transfected with zalpha11receptor (BaF3/hzalpha11 cells) as controls. Zalpha11 Ligand binding toBaF3/hzalpha11 cells was expected (positive control), while no bindingto wild-type BaF3 cells was expected (negative control), based onproliferation assay results (Example 2). About 5×10⁵ Raji cells/well,1×10⁶ BaF3/hzalpha11 and 1×10⁶ BaF3 cells cells/well, were each platedin 96-well plates. Ten ng/ml of labeled human zalpha11 Ligand was addedin duplicate to wells, with a dilution series of unlabeled humanzalpha11 Ligand competitor added from 250 fold molar excess in 1:4dilutions down to 0.061 fold molar excess. Each point was run induplicate. After the labeled human zalpha11 Ligand was added to wells,it was allowed to incubate at 4° C. for 2 h to allow for binding ofLigand to the cells. The cells were then washed 3× in binding buffer(RPMI-1710 (JRH Biosciences) with 1% BSA (Sigma)), and counted on theCOBRA II AUTO-GAMMA gamma counter (Packard Instrument Company, Meriden,Conn.).

Binding of the labeled zalpha11 Ligand to cells was evident in the Rajiand the BaF3/hzalpha11 cells. In addition, for Raji cells, an average250 fold molar excess of unlabeled zalpha11 Ligand decreased binding 3fold in the presence of a non-specific unlabeled competitor (InterferonGamma from R&D Systems, Minneapolis, Minn.), and 3.7 fold relative to nocompetitor. Competition was observed in a dose dependent fashion for thespecific unlabeled competitor, human zalpha11 Ligand. Thus, the zalpha11Ligand binding to Raji cells was specific. Similarly, for positivecontrol BaF3/zalpha11 cells, the 250 fold molar excess of unlabeledzalpha11 Ligand decreased binding 2 fold relative to the non-specificcompetitor and 3.06 fold relative to no competitor. Thus, the zalpha11Ligand binding to BaF3/zalpha11 cells also was specific. No competablebinding was observed with the wild-type BaF3 cells. Thus, the zalpha11Ligand was shown to bind specifically to Raji cells, and toBaf3/hzalpha11 cells, but not to the negative control Baf3 cells.

The bound radiolabeled zalpha11 Ligand is then cross-linked to themolecule to which it binds on the cell surface of Raji cells usingstandard cross-linking methods, to identify the receptor complex towhich it binds on these cells. Moreover, anti-zalpha11 receptorantibodies (Example 24 and Example 10), and other anti-cytokine receptorsubunit antibodies are employed to assess which subunit componentscomprise a functional hzalpha11 receptor complex, for example, on theRaji cells and other cell lines to which zalpha11 Ligand binds. Suchantibodies can be used to compete for zalpha11 Ligand in a binding assayas described above, and hence show which receptor subunits are presentof the Raji cell surface, and on other cell lines to which zalpha11Ligand binds. Moreover, such antibodies can be used to immunoprecipitateradiolabeled zalpha11 Ligand cross-linked material using methods knownin the art and described herein. In addition anti-zalpha11 Ligandantibodies (commonly owned U.S. patent application Ser. No. 09/522,217)can be used to immunoprecipitate radiolabeled zalpha11 Ligandcross-linked material.

Example 33 Zalpha11 Receptor Expression on Human Blood Cells

A. Preparation and Culture of Human Peripheral Blood Cells

Fresh drawn human blood was diluted 1:1 with PBS (GIBCO BRL) and layeredover Ficoll/Hypaque Plus (Pharmacia LKB Biotechnology Inc., Piscataway,N.J.) and spun for 30 minutes at 1800 rpm and allowed to stop with thebrake off. The interface layer was removed and transferred to a fresh 50ml Falcon tube (Falcon, VWR, Seattle, Wash.), brought up to a finalvolume of 40 ml with PBS and spun for 10 minutes at 1200 rpm with thebrake on. The viability of the isolated cells was tested using TrypanBlue (GIBCO BRL) and the cells were resuspended at a final concentrationof 1×10⁶ cells/ml cell medium (RPMI Medium 1640, 10% Heat inactivatedfetal bovine serum, 5% L-glutamine, 5% Pen/Strep) (GIBCO BRL).

Cells were cultured in 6 well plates (Falcon, VWR) for 0, 4 or 24 hourswith a variety of different stimuli described below. Anti-IgM, anti-CD40and anti-CD3 stimulation were done as in Example 26. Phorbol myristateacetate (PMA) and ionomycin (Sigma, St. Louis, Mo.) were added toappropriate wells at 10 ng/ml and 0.5 mg/ml respectively. The cells wereincubated at 37° C. in a humidified incubator for various times.

B. Antibody Staining and Analysis

Cells were collected out of the plates, washed and resuspended in icecold staining media (HBSS, 1% fetal bovine serum, 0.1% sodium azide) ata concentration of about ten million cells per milliliter. Blocking ofFc receptor and non-specific binding of antibodies to the cells wasachieved by adding 10% normal goat serum (Gemini Bioproducts, Woodland,Calif.) and 10% normal human serum (Ultraserum, Gemini) to the cellsuspension. Aliquots of the cell suspensions were mixed with a FITClabeled monoclonal antibody against one of the lineage markers CD3, CD19or CD14 (PharMingen, La Jolla, Calif.) and a biotinylated monoclonalantibody against the human zalpha11 receptor (hu-zalpha11) (Example 24).After incubation on ice for 60 minutes the cells were washed twice withice cold staining media and resuspended in 50 ml staining mediacontaining streptavidin-PE (Caltag, Burlingame, Calif.). After a 30minute incubation on ice, the cells were washed twice with ice cold washbuffer (PBS, 1% fetal bovine serum, 0.1% sodium azide) and resuspendedin wash buffer containing 1 mg/ml 7-AAD (Molecular Probes, Eugene,Oreg.) as a viability marker. Flow data was acquired on living cellsusing a FACSCalibur flow cytometer (BD Immunocytometry Systems, SanJose, Calif.). Both acquisition and analysis were performed usingCellQuest software (BD Immunocytometry Systems).

Results showed that the human zalpha11 receptor is expressed on humanperipheral blood cells expressing either CD3, CD19 or CD14. Activationof either T cells with anti-CD3 or B cells with anti-CD40 resulted in anincreased level of cell surface zalpha11 at 24 hours. No increase in thelevel of expression of zalpha11 was seen at 4 hours with any stimulus oneither cell population. Treatment of the cells with zalpha11 ligandresulted in a decrease of zalpha11 staining on CD3 positive and CD19positive cells but not CD14 positive cells at both 4 and 24 hours.

Example 34 Human Zalpha11 Ligand Activity is Blocked with Anti-IL-2RγAntibodies in a BaF3/Zalpha11 Proliferation Assay

The role of the IL-2□ receptor was investigated using anti-IL-2□receptor monoclonal antibodies to assess whether they would blockzalpha11 Ligand activity in a BaF3/zalpha11 proliferation assay (Example2). Conditioned-media from BHK570 cells transfected with the humanzalpha11 Ligand was added to the assay at 5%, 2.5%, 1.25% and 0.625%concentrations, with or without IL-2 receptor antibodies.

The following mouse anti-IL-2 receptor monoclonal antibodies fromPharMingen International, San Diego, Calif. were added at 50 □g/ml each:(a) 4G3+TUGm2 or (b) TM-□1. 4G3 and TUGm2 are purified rat anti-mouseγ_(C) chain antibodies, TM-□1 is a purified rat anti-mouse CD122 (IL-2receptor □ chain) antibody. Assay results demonstrated almost completeinhibition of the zalpha11 Ligand response with the 4G3+TUGm2 antibodycombination in comparison to the no-antibody control. The TM-□1 antibodyhad no effect. These results suggest a role for the IL-2□ receptor inthe zalpha11 Ligand proliferative response, and further supports thatthe IL-2Rγ heterodimerizes with the zalpha11 receptor to elicit thatresponse.

Example 35 Post-Translational Mannosylation of Zalpha11 ReceptorPolypeptide on a Highly Conserved Trp Residue

Mannosylation of the human zalpha11 receptor was assessed using themethod for C-2 mannosylation of Tryptophan as described in Hofsteenge, Jet al., Biochemistry 33:13524-13530, 1994, and Loeffler, A et al.,Biochemistry 35:12005-14, 1996. Moreover, these investigators showedthat in a motif of amino acids, WXXW (SEQ ID NO:67), that Trp can bemannosylated.

A soluble zalpha11 receptor bearing a C-terminal Glu-Glu (CEE) (SEQ IDNO:14) or FLAG (SEQ ID NO:23) tag was expressed in BHK cells andpurified by anti-Flag or anti-EE affinity chromatography (Example 4A). Asoluble zalpha11 receptor C-terminally tagged with an Fc4 tag (SEQ IDNO:25) and expressed in CHO cells was affinity purified by anti-Fc4affinity chromatography (Example 4B). These polypeptides wereenzymatically cleaved to generate peptide fragments for the study.

All enzymatic digestions were performed overnight at a proteinconcentration of 1.0 mg/ml. PNGaseF (Oxford GlycoSciences, Abingdon,Oxford UK) digestion was performed by diluting each soluble zalpha11receptor polypeptide into a 50 mM EDTA, 20 mM Na-Phosphate pH 7.5 bufferand incubating it with 0.4 U of enzyme per μg of protein. Glu-C (RocheMolecular Biochemicals, Indianapolis, Ind.) digestion was performed at a1:50 ratio of enzyme to protein by buffer exchanging the sample into 25mM NH₄HCO₃ pH 7.8 and incubating it at 25° C., except for the Fc4 taggedmaterial, which was digested in 50 mM Na-Phosphate pH 7.8+5%Acetonitrile (EM Science, Darmstadt, Germany) at 37° C. The Glu-Cdigestion generated a zalpha11 WSXWS-containing peptide as shown fromamino acid 178 (Leu) to amino acid 199 (Ser) of SEQ ID NO:6 (197 (Leu)to amino acid 218 (Ser) of SEQ ID NO:2). Asp-N (Roche MolecularBiochemicals, Indianapolis, Ind.) digestion was performed by bufferexchanging the protein into 50 mM Na-Phosphate pH 7.7 and incubating itat 37° C. with enzyme at a 1:50 ratio to zalpha11 receptor polypeptide.The Asp-N digestion generated a zalpha11 WSXWS-containing peptide asshown from amino acid 179 (Glu) to amino acid 210 (Ser) of SEQ ID NO:6(198 (Leu) to amino acid 229 (Glu) of SEQ ID NO:2).

LCMS and LCMS-MS analyses were performed on a Magic HPLC (MichromBioresources, Auburn, Calif.) connected in-line to a Finnigan LCQ massspectrometer (Finnigan MAT, San Jose, Calif.). LC separation was done ona Vydac C4 5μ 300 Å column (Michrom Bioresources) with an elutiongradient of 20%-80% solvent B over 80 minutes where solvent A was 2%Acetonitrile+0.1% TFA and solvent B was 90% Acetonitrile+0.095% TFA (EMScience; Sigma, St. Louis, Mo.). The LCQ mass spectrometer was set tocollect MS spectra for the duration of the run. LCMS-MS analysis ofpolypeptide digests was performed on the same instrument system using aVydac C18 5μ 300 Å column (Michrom Bioresources) with an elutiongradient of 5-65% solvent B over 80 minutes with the same solvent systemdescribed for LCMS analysis above. The LCQ mass spectrometer wasconfigured to collect MS, zoom-scan and MS-MS spectra for each ion overa minimum threshold.

The extent of tryptophan mannosylation was estimated by comparing ionintensities for the 2+ and 3+ ions of the peptides containing the WSXWSmotif (SEQ ID NO:13) from both Glu-C and Asp-N digestion describedabove. Peak composition was first determined utilizing the MS data and apeptide map was generated. Next, an average spectrum was createdstarting approximately 1 minute before the early eluting mannosylatedWSXWS (SEQ ID NO:13) containing peptide and ending approximately 1minute after its later eluting non-mannosylated companion peptide. Thenormalized intensities of the ions corresponding to mannosylated andnon-mannosylated peptide were compared and used to generate a percentageoccupancy number. Values generated for both 2+ and 3+ charge states wereaveraged to generate a percent occupancy value for each digest. Thisvalue was then averaged with the value from the companion digest foreach lot of protein to generate a final value.

Table 7 below summarizes the data that were calculated for eachPeptide-tag and host cell used for zalpha11 soluble receptor expression.

TABLE 7 C-terminal-Tag Expression Host % WSXWS Mannosylated Glu-Glu BHK~46% FLAG BHK ~35% Fc4 CHO ~11%

One of skill in the art would appreciate that mannosylation ornon-mannosylation of the zalpha11 receptor WSXWS motif (SEQ ID NO:13)can affect the ability of the zalpha11 receptor or zalpha11 solublereceptor to homodimerize, heterodimerize, and/or it's ability to bindthe zalpha11 Ligand. As the mannosylation on zalpha11 receptor appearsto differ depending on the cell type in which the receptor so expressed,optimization of the expression and production of zalpha11 receptor andsoluble receptor polypeptides may take into consideration whether thezalpha11 receptor produced by the cell is mannosylated ornon-mannosylated. As such, one of skill in the art would appreciate thatthe polypeptides of the present invention can be either mannosylated ornon-mannosylated.

As the mannosylation event is within the WSXWS motif (SEQ ID NO:13) ofthe zalpha11 class I cytokine receptor, the mannosylation of the Trp orthe lack thereof can affect the polypeptide functionally. For example,insertions or deletions in the WSXWS motif (SEQ ID NO:13) of the EPORcan abrogate cell surface expression, destroy or reduce proliferativeresponse, decrease receptor internalization, and affect EPO binding(Yoshimura, A et al., J. Biol. Chem. 267:11619-11625, 1992; Quelle, D Eet al., Mol. Cell. Biol. 12:4553-4561, 1992; Hilton, D J et al., Proc.Natl. Acad. Sci. USA 92:190-194, 1995). However, mutation in the WSXWSmotif (SEQ ID NO:13) can also result in more efficient export from theER and greater expression of the receptor on the cell surface (Hilton, DJ et al., supra.). Effects on cell surface expression, ligand bindingand stimulatory response have also been seen with studies on WSXWS motif(SEQ ID NO:13) and related motifs in mutational analysis on IL-2Rβ,GM-CSFR, and GHR (Miyazaki, et al., EMBO J. 10:3191-3197, 1991; Ronco,L. V. et al., J. Biol. Chem. 269:277-283, 1994; Baumgartner, J W et al.,J. Biol. Chem. 269:29094-29101, 1994).

Similarly, mannosylation of the first Trp residue in the WSXWS motif(SEQ ID NO:13) of zalpha11 receptor polypeptides, including full-lengthand soluble receptors described herein, can have important structuraland functional implications such as having affects on the overallstability of the receptor, rate of proteolysis, intracellularprocessing, antigenicity, cell surface expression, dimerization ormultimerization, co-receptor binding, signaling or internalization,affects on zalpha11 Ligand binding and stability of receptor-ligandinteraction. Comparison of mannosylated and non-mannosylated zalpha11receptors can be made using X-ray crystallography or NMR on purifiedzalpha11 polypeptides (e.g., soluble receptors), or functional studiescomparing zalpha11 expressed in cell lines that either mannosylated(e.g., BHK or other cell line) or are defective or reduced inmannosylation (e.g., CHO or other cell line) and comparing the receptorsin the various assays described herein.

Example 36 BHK Transfectant Binding Studies

Purified human zalpha11 Ligand (25 μg) protein (commonly owned U.S.patent application Ser. No. 09/522,217) was iodinated with ¹²⁵I(Amersham) using iodo-beads (Pierce) and purified on a Sephadex G25PD-10 column (Pharmacia). BHK transfectants (Example 31) expressingeither human zalpha11 alone or human zalpha11+human IL-2R□ receptor wereplated at 30K/well in a 24-well dish 24 hours prior to the bindingstudy. BHK transfectants were incubated for 2 hours at 4° C. with 2.5 ng(0.147 pMoles) ¹²⁵I zalpha11 Ligand (specific activity 6.4×10⁷ cpm/ug)in the presence of various concentrations of cold zalpha11 Ligand (in arange from about a 10,884 fold excess to no competition in 15, 4-folddilutions). Cells were washed three times with binding buffer beforelysis in 0.8 M NaOH, followed by gamma emission counting. Analysis ofthese data yielded an affinity of approximately 1 nM for the zalpha11transfectants and approximately 0.1 nM for the human zalpha11+humanIL-2R□ receptor transfectants. This result suggested that zalpha11Ligand has high affinity on both the homodimeric human zalpha11 orheterodimeric human zalpha11+human IL-2R□ receptor, and that theaffinity is higher for the heterodimer.

Example 37 Murine Homodimeric Zalpha11 Receptor-mG2a Fusion Protein

The expression vector pEZE2 was used to express the murine zalpha11receptor-murine IgGamma2a Fc fusion protein (zalpha11m-mG2a). The mousezalpha11 extracellular domain murine immunoglobulin gamma 2a heavy chainFc region fusion protein (zalpha11m-mG2a) DNA sequence is shown in SEQID NO:72, and the corresponding polypeptide sequence is shown in SEQ IDNO:73.

The pEZE2 vector is a plasmid derived from pDC312 (Immunex Corp.,Seattle, Wash.), and contains an EASE segment as described in WIPOPublication WO 97/25420. The presence of the EASE segment in anexpression vector can improve expression of recombinant proteins abouttwo to eight fold in stable cell pools. The pEZE2 plasmid is adicistronic expression vector that can be used to express two differentproteins in mammalian cells, such as Chinese Hamster Ovary (CHO) cells.The pEZE2 expression unit contains a CMV enhancer/promoter; anadenovirus tripartite leader sequence; a multiple cloning site (MCS) forinsertion of the coding region for the recombinant protein of interest;an encephalomyocarditis virus internal ribosome entry site; a codingsegment for mouse dihydrofolate reductase; and the SV40 transcriptionterminator. In addition, pEZE2 contains an E. coli origin of replicationand the bacterial beta lactamase gene.

The zalpha11m-mG2a fusion protein is a disulfide-linked homodimerconsisting of two chains of the mouse zalpha11 extracellular domainfused to a wild type murine immunoglobulin gamma 2a Fc region. Themurine immunoglobulin gamma 2a Fc confers effector functions, FcγRIbinding and C1q complement fixation.

The mouse zalpha11 extracellular domain murine immunoglobulin gamma 2aFc constant region fusion construct was generated by overlap PCR ofthree separate DNA fragments, each generated by separate PCRamplification reactions. The first fragment contained an optimized tPA(tissue plasminogen activator) signal sequence (SEQ ID NO:80). Theoptimized tPA (otPA) signal sequence was amplified using oligonucleotideprimers ZC26,644 (SEQ ID NO:74) and ZC26,641 (SEQ ID NO:75) using anin-house previously generated expression vector as the template. PCRreaction mix contained 20 pmoles of each primer, 10 ng template cDNA, 20μM each dNTP, 1× Taq buffer (Life Technologies, Gaithersburg, Md.), 0.5μl Taq polymerase in a 100 μl reaction. PCR conditions: 1 cycle, 94° C.,2 minutes, 25 cycles, 94° C., 30 seconds, 60° C., 30 seconds, 72° C., 30seconds, 1 cycle, 72° C., 5 minutes. The second fragment contained themouse zalpha11 extracellular domain coding region of amino acids 20 to257 of SEQ ID NO:12. Oligonucleotide primers ZC26,642 (SEQ ID NO:76) andZC26,662 (SEQ ID NO:77) were used to amplify this mouse zalpha11 segmentusing a previously generated clone of mouse zalpha11 (SEQ ID NO:11) asthe template. This PCR fragment was made using the same PCR reaction mixspecified above. PCR reaction conditions were as follows: 1 cycle, 94°C., 2 minutes, 25 cycles, 94° C., 30 seconds, 50° C., 30 seconds, 72°C., 45 seconds, 1 cycle, 72° C., 5 minutes.

The murine gamma 2a heavy chain Fc region was generated from apreviously generated clone of murine Ig gamma 2a heavy chain cDNA. Thesegment containing the hinge, C_(H)2, and C_(H)3 domains of the murineimmunoglobulin gamma 2a heavy chain constant region was generated by PCRamplification using oligonucleotide primers ZC26,643 (SEQ ID NO:78) andZC26,645 (SEQ ID NO:79). This PCR fragment was made using the samereaction mix specified above. PCR conditions were as follows: 1 cycle,94° C., 2 minutes, 25 cycles, 94° C., 30 seconds, 60° C., 30 seconds,72° C., 30 seconds, 1 cycle, 72° C., 5 minutes.

To prepare the fusion protein-coding segment, three protein codingdomains were linked by overlap PCR using oligonucleotides ZC26,644 (SEQID NO:74) and ZC26,662 (SEQ ID NO:77) to link the first two PCR productsand ZC26,644 (SEQ ID NO:74) and ZC26,645 (SEQ ID NO:79) to link in theFc region. Two reactions were set up: The first ran 25 cycles of 94° C.for 2 min., 55° C. for 30 sec. and 72° C. for 1 min. 30 sec. The otherreaction ran 25 cycles of 94 degrees C. for 2 min., 60° C. for 30 secand 72° C. for 1 min. and 30 sec. The PCR products in the two reactionswere pooled and purified by using the QIAquick PCR purification kit(Qiagen) as per manufacturer's protocol. The product was eluted in 60 μlof buffer. 30 μl of this eluate was digested with Fse1 and Asc1restriction enzymes in diluted NEB 10× buffer No. 4 (New EnglandBiolabs, Beverly, Mass.) as per manufacturer's directions. The materialwas then run on a 1% TAE agarose gel and the approximately 1500 bp bandwas excised and the DNA purified using a Qiagen Agarose gel extractionkit (Qiagen) as per manufacturers instructions. The fragment was elutedin 30 μl H₂O.

To prepare the recipient vector for the insert, about 3 μg of pEZE2vector was digested w/Asc1 and Fse1 in the same manner as above, withthe exception of 1 μl of Calf Intestinal Phosphatase (CIP) (New EnglandBiolabs) added after restriction enzyme digest (the reaction was allowedto proceed an additional 2 hrs). The vector was then run on an agarosegel and purified as per above. The material was eluted in 30 μl of H2O.

The fusion protein-coding segment was cloned into the MCS of pEZE2 fromthe FseI site to the AscI site in the polylinker, and ligated in 20 μlusing standard molecular biological reagents and procedures. Theligation reaction was incubated O/N at 16° C. About 4 μl of thisligation mix was electroporated into 50 μl of DH12s E. Colielectrocompetent cells (Life Technologies, Rockvelle, Md.) and the cellsrescued in 1 ml of LB media and allowed to shake/incubate for 1 hr. and100 μl spread on Amp 100 agar plates. The plates were allowed toincubate o/n at 37° C. A single colony was sequence analyzed. A mutationwas found that would result in a change from Glu to Lys at position 25in SEQ ID NO:73. This amino acid substitution is within the otPA leader,and may have resulted in improper processing of the signal peptide, asN-terminal showed that the leader sequence was incompletely cleaved andstarted at a pyroglutamine residue upstream of the predicted start.However, this homodimeric construct was still active in inhibiting thezalpha11 Ligand (Example 40).

A large prep was created using the Qiagen Maxi prep kit (Qiagen) as permanufacturers instructions. The plasmid was used to transfect CHO cells.The cells were selected in medium without hypoxanthine or thymidine andthe transgene was amplified using methotrexate (Example 38). Thepresence of protein was assayed by Western blotting using anti humangamma 1 heavy chain constant region and anti human kappa light chainantibodies (Rockland Immunochemicals, Gilbertsville Pa.).

Example 38 Production of zAlpha11m-mG2A in DG-44 CHO Cells

20 μg of a zAlpha11m-mG2A/pEZE2 construct (Example 37) was digested with40 units of Pvu I at 37° C. for three hours and was then precipitatedwith isopropanol and pelleted in a 1.5 mL microfuge tube. Thesupernatant was aspirated away from the pellet and the pellet wasresuspended in 100 μl of water. About 200 μg (20 μl) of sheared salmonsperm DNA was added to the digested zAlpha11m-mG2A/pEZE2 construct. TheDNA mixture was co-precipitated using 0.1 volumes of sodium acetate (pH5.2) and 2.2 volumes of ethanol. The tube was placed on dry ice for 15minutes then was spun down in a microfuge at 14,000 RPM for 15 minutesforming a DNA pellet. The supernatant was aspirated off the pellet, andthe pellet was washed with 1 mL of 70% ethanol and allowed to incubatefor 5 minutes at room temperature. The tube was spun in a microfuge for10 minutes at 14,000 RPM and the supernatant was aspirated off thepellet. The pellet was allowed to air dry for 30 minutes. The pellet wasthen resuspended in 100 μl of water and allowed to incubate at roomtemperature for 10 minutes. 500 μl containing about 5×10⁶ DG-44 CHOcells was added to the DNA in the microfuge tube, then the DNA/cellmixture was placed in a 0.4 cm gap cuvette and electroporated using thefollowing parameters: 1,070 μF, high capacitance and 376 V. The contentsof the cuvette were then removed and diluted to 25 mLs with EX-CELL™ 325PF-CHO Protein Free Media (JRH Biosciences, Lenexa, Kans.) with 3 mML-Glutamine and placed in a 125 mL shake flask. The flask was placed inan incubator on a shaker at 37° C., 6% CO₂ and shaking at 120 RPM.

The DG-44 CHO zAlpha11m-mG2A culture was amplified with methotrexate(MTX) using standard methods to a final MTX level of 50 nM MTX. Theculture was dilution-cloned and screened using a series of westernblots. A final clone was chosen and further selected in MTX to a levelof 200 nM MTX and was then scaled up for production. Production of eachlot of the clone was accomplished by seeding 8×4 L spinner flasks with 2L of culture at approximately 5×10⁵ cells/mL. Cultures were spun at 70RPM, maintained at 37° C., 6% CO₂ and allowed to incubate for either 72or 96 hours. The cells were spun down and the supernatants were 0.2 μmfiltered. A sufficient number of cells were recovered to seed the nextseries of flasks. Four total lots were produced in this manner forprotein purification (Example 39).

Example 39 Purification of the Homodimeric Zalpha11m-mG2a SolubleReceptor Protein

All procedures performed at 4° C., unless otherwise noted. Conditionedmedia (Example 38) was directly captured on an appropriately sized POROS50 A (coupled protein A; PerSeptive BioSystems, Framingham, Mass.)column at an optimal capture flow rate. The column was washed with 20column volumes (CV) of loading buffer, then rapidly eluted with 3 CV of0.1 M Glycine pH 2.5. The collected fractions had a predetermined volumeof 2 M TRIS pH 8.0 added prior to the elution to neutralize the pH toabout 7.2.

Brilliant Blue (Sigma) stained NuPAGE gels were ran to analyze theelution. Fractions of interested were pooled and concentrated against a30 kD MWCO centrifugal concentrator to a nominal volume. Theconcentrated Protein A pool was injected onto an appropriately sizedPhamicia Sephacryl 200 column (Pharmacia) to remove aggregates and tobuffer exchange the protein into PBS pH 7.2.

Brilliant Blue (Sigma) stained NuPAGE gels (NOVEX) were again used toanalyze the elution. Fractions were pooled and concentrated as before to˜1-2 mgs/ml. Western and Brilliant Blue (Sigma) stained NuPAGE gels(NOVEX) were ran to confirm purity and content. In addition, the proteinwas submitted for amino acid analysis (AAA), and N-terminal sequencingfor further analysis.

Example 40 Soluble Homodimeric Zalpha11m-mg2a Fusion Protein as aZalpha11 Ligand Antagonist

BaF3 cells stably expressing the mouse zalpha11 receptor (constructed asper Example 2 using primers to SEQ ID NO:11) were plated at 5500 cellsper well in standard 96-well tissue culture plates in base medium plus 3ng/ml human zalpha11 Ligand. Base medium is 500 ml RPMI 1640 (JRHBiosciences), 5 ml 100× Sodium Pyruvate (Gibco BRL), 5 ml 100×L-glutamine (Gibco BRL), and 50 ml heat-inactivated Fetal Bovine Serum(FBS) (Hyclone Laboratories). To the cells, a decreasing dose of eitherpurified homodimeric zalpha11m-mg2a (Example 39) was added. An AlamarBlue proliferation assay was run and fluorimetry performed as perExample 2B.

The homodimeric zalpha11m-mG2a fusion protein inhibited human zalpha11Ligand activity in a dose dependent manner, with 1-5 μg/ml able toinhibit the activity of 1.25 ng/ml human zalpha11 Ligand.

From the foregoing, it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. An isolated polynucleotide encoding a heterodimeric receptor complexcomprising two soluble receptor subunits, wherein the first solublereceptor subunit comprises a soluble receptor polypeptide comprising thesequence of amino acid residues as shown in SEQ ID NO:6, and wherein thesecond soluble receptor subunit comprises a soluble IL-2Rγ receptorpolypeptide (SEQ ID NO:4).
 2. The isolated polynucleotide encoding aheterodimeric receptor complex according to claim 1, wherein theheterodimeric receptor complex binds a ligand comprising a zalpha11Ligand (IL-21) polypeptide (SEQ ID NO:10).
 3. The isolatedpolynucleotide encoding a heterodimeric receptor complex according toclaim 1, wherein the heterodimeric receptor complex antagonizes theactivity of a ligand comprising a zalpha11 Ligand (IL-21) polypeptide(SEQ ID NO: 10).
 4. The isolated heterodimeric soluble complex accordingto claim 1, wherein the soluble receptor complex further comprises anaffinity tag, label, chemical moiety, toxin, biotin/avidin label,radionuclide, enzyme, substrate, cofactor, inhibitor, fluorescentmarker, chemiluminescent marker, toxin, cytotoxic molecule or animmunoglobulin Fc domain.
 5. The isolated polynucleotide encoding aheterodimeric receptor complex consisting of two soluble receptorsubunits according to claim 1, wherein the first soluble receptorsubunit consists of a soluble receptor polypeptide comprising thesequence of amino acid residues as shown in SEQ ID NO: 6, and the secondreceptor subunit consists of a soluble receptor polypeptide comprisingsoluble IL-2Rγ receptor polypeptide (SEQ ID NO:4).
 6. The isolatedpolynucleotide encoding a heterodimeric receptor complex according toclaim 5, wherein the heterodimeric receptor complex binds a ligandcomprising a zalpha11 Ligand (IL-21) polypeptide (SEQ ID NO:10).
 7. Theisolated polynucleotide encoding a heterodimeric receptor complexaccording to claim 5, wherein the heterodimeric receptor complexantagonizes the activity of a ligand comprising a zalpha11 Ligand(IL-21) polypeptide (SEQ ID NO:10).
 8. The isolated polynucleotideencoding a heterodimeric receptor complex according to claim 5, whereinat least one of the soluble receptor subunits further comprises anaffinity tag, label, chemical moiety, toxin, biotin/avidin label,radionuclide, enzyme, substrate, cofactor, inhibitor, fluorescentmarker, chemiluminescent marker, toxin, cytotoxic molecule or animmunoglobulin Fc domain.
 9. An expression vector comprising thefollowing operably linked elements: (a) a transcription promoter; afirst DNA segment encoding a soluble receptor polypeptide comprising theamino acid sequence as shown in SEQ ID NO:6; and a transcriptionterminator; and (b) a second transcription promoter; a second DNAsegment encoding a soluble receptor polypeptide comprising IL-2Rγreceptor polypeptide (SEQ ID NO:4); and a transcription terminator; andwherein the first and second DNA segments are contained within a singleexpression vector or are contained within independent expressionvectors.
 10. The expression vector according to claim 9, furthercomprising a secretory signal sequence operably linked to the first andsecond DNA segments.
 11. A cultured cell comprising an expression vectoraccording to claim 9, wherein the cell expresses the polypeptidesencoded by the DNA segments and wherein the polypeptides expressed fromthe DNA segments form a heterodimeric complex.
 12. A cultured cellcomprising an expression vector according to claim 9, wherein the firstand second DNA segments are located on independent expression vectorsand are co-transfected into the cell, and cell expresses thepolypeptides encoded by the DNA segments.
 13. A cultured cell comprisingan expression vector according claim 9, wherein the cell expresses aheterodimeric receptor polypeptide encoded by the DNA segments.
 14. Thecell according to claim 11, wherein the cell secretes a soluble receptorpolypeptide heterodimer complex that binds a ligand comprising azalpha11 Ligand (IL-21) polypeptide (SEQ ID NO: 10).
 15. The cellaccording to claim 11, wherein the cell secretes a soluble receptorpolypeptide heterodimer complex that antagonizes the ligand activity ofa ligand comprising a zalpha11 Ligand (IL-21) polypeptide (SEQ IDNO:10).